1) The basic idea: what “changing the surname” really means in civil registry terms

In the Philippine civil registry system, a child’s surname is not “changed” the way a nickname is changed. What happens is usually one of these:

An annotation is placed on the child’s birth record stating that the father has acknowledged paternity and that the child will use the father’s surname (the common scenario after an Affidavit of Acknowledgment/Admission of Paternity and an Affidavit to Use the Surname of the Father).
The record is annotated for legitimation after the parents marry, which changes the child’s status from illegitimate to legitimate and can affect the child’s name.
A court-ordered change or correction is made (for cases that cannot be handled administratively).

The PSA (Philippine Statistics Authority) is the national repository and issuer of civil registry documents. The Local Civil Registry Office (LCRO) is where you typically file the request and submit documents; the PSA is where you later request the annotated PSA birth certificate.

2) Key legal framework (Philippine context)

A. Illegitimate children and use of the father’s surname

Under Republic Act No. 9255 (and its implementing rules), an illegitimate child may use the father’s surname if the father acknowledges paternity.

Important points commonly misunderstood:

Acknowledgment of paternity does not automatically make the child legitimate. Legitimacy changes primarily through legitimation (subsequent marriage of parents, with legal requisites).
Using the father’s surname is generally treated as an option available upon proper acknowledgment and documentation, not an automatic rewrite of the record without process.

B. Judicial routes remain for situations outside RA 9255’s scope

If the request does not fit the administrative mechanism (for example, a legitimate child’s surname or complex identity disputes), the remedy often shifts to:

Rule 103 (Change of Name) and/or
Rule 108 (Correction/Cancellation of Entries in the Civil Register) through court proceedings, depending on what exactly needs to be changed and whether it is substantial or controversial.

3) Terms and documents you will keep encountering

1) Affidavit of Acknowledgment/Admission of Paternity (or similar)

This is the father’s sworn statement acknowledging that he is the biological father. Variations exist in title, but the function is the same: recognition/acknowledgment.

2) Affidavit to Use the Surname of the Father (AUSF)

This is the sworn statement used to implement the child’s use of the father’s surname under RA 9255.

General rule in practice:

For a child below 18, the affidavit is executed by the mother (as the parent exercising parental authority) or legal guardian, with the father’s acknowledgment documents supporting it.
For a child 18 and above, the child typically executes the affidavit personally, with supporting recognition documents.

3) “Annotation”

An “annotation” is an official note printed on the birth certificate record (and reflected on the PSA-issued copy later). It is the civil registry system’s standard way of recording later events affecting civil status/name usage without replacing the original entry.

4) When an affidavit-based process works—and when it doesn’t

A. Situations commonly covered by RA 9255 administrative process

This is the usual “after affidavit of paternity” scenario:

Child is illegitimate
Birth was registered using the mother’s surname
Father later executes an Affidavit of Acknowledgment/Admission of Paternity (or signs acknowledgment in another acceptable form)
The proper party executes an AUSF
The civil registrar processes it for annotation, and the PSA eventually reflects that annotation

B. Situations that often require something more than affidavits

Affidavits alone are often not enough when:

The child is legitimate (born within a valid marriage).
- A legitimate child’s surname follows legitimacy rules; changing it typically requires a court process (and must meet stringent standards).
The father’s name/details were recorded incorrectly (identity issues, wrong first name, wrong person, etc.).
- Depending on the error, this may require an administrative correction procedure (for clerical errors) or a judicial correction for substantial matters.
There is a dispute (mother contests paternity, father contests paternity, or conflicting records).
- Disputed status/identity issues typically require court determination.
The requested outcome is to remove the father’s surname after already using it.
- This is generally treated as a substantial change and commonly leans toward judicial relief, especially if it affects identity continuity and public records.

5) PSA/LCR: where you file vs. where you get the final birth certificate

Where you FILE

Typically at the Local Civil Registry Office (LCRO):

LCRO where the birth was registered, or
In many local practices, the LCRO where the applicant resides, which then transmits to the LCRO of record (implementation can vary by locality).

Where you GET the annotated certificate

After approval and transmission:

You request the PSA-issued birth certificate (often described as the “annotated” PSA copy).

6) Core documentary requirements (what PSA/LCRO typically requires)

Requirements can vary slightly by LCRO, but the standard set generally includes:

A. Civil registry documents

Certified true copy / LCRO copy of the Certificate of Live Birth (COLB) of the child (or at least details sufficient for the registrar to locate it)
PSA copy of the child’s birth certificate (some offices ask for this as reference; others rely on the registry copy)

B. Proof of acknowledgment

At least one acceptable form that shows the father recognized the child, such as:

Affidavit of Acknowledgment/Admission of Paternity, duly notarized, or
Acknowledgment executed in a recognized civil registry form

C. The implementing affidavit

Affidavit to Use the Surname of the Father (AUSF), duly notarized

D. Identification and supporting papers

Valid government IDs of the mother/father (as applicable) and/or the adult child
If the child is a minor: documents showing the filer’s authority (e.g., mother’s ID; sometimes the child’s school ID, baptismal certificate, or other supporting documents if requested)
If representative files: Special Power of Attorney and IDs

E. Other possible supporting documents (as required by the LCRO)

Depending on circumstances:

Proof of the father’s identity (additional IDs or documents)
If the father is abroad: consularized/acknowledged documents executed before a Philippine consular officer, or properly authenticated as required by prevailing rules in the relevant jurisdiction
If the father is deceased: additional documents may be required to establish identity and acknowledgment, depending on what exists on record

Practical note: LCROs are strict about consistency of names, dates, and personal details across documents. Even minor inconsistencies can cause delays or require additional affidavits or corrections.

7) Step-by-step process: changing surname after affidavit of paternity (typical RA 9255 route)

Step 1: Prepare and notarize the affidavits

Execute the Affidavit of Acknowledgment/Admission of Paternity (if not already executed in an acceptable form).
Execute the AUSF (by the proper party: usually the mother/guardian if minor; the child if already of age).
Ensure the affidavits contain correct and complete identifying details: full names, birth details, addresses, and clear statements of acknowledgment and surname use.

Step 2: File with the LCRO (submission and evaluation)

Submit the documentary requirements to the LCRO.
Pay filing/processing fees (fees vary by locality).
The civil registrar evaluates sufficiency and authenticity, and checks the child’s birth record.

Step 3: Civil registrar action and annotation at the local level

If approved, the LCRO processes the request and prepares the needed civil registry endorsements/annotations.
The birth record is annotated according to the implementing rules, reflecting that the child will use the father’s surname.

Step 4: Endorsement/transmittal to PSA

The LCRO transmits the annotated record (or the civil registry action) to the PSA for inclusion in the PSA database.

Step 5: Request the annotated PSA birth certificate

After sufficient time for PSA posting, request a PSA copy of the birth certificate.
Verify that the PSA copy now shows the annotation reflecting the child’s use of the father’s surname.

8) What the PSA birth certificate typically looks like afterward

After the process, PSA copies usually reflect:

The original entries remain part of the record
An annotation appears indicating the father’s acknowledgment and the child’s use of the father’s surname under the relevant law/rules

Because civil registry practices are record-based, the “change” is not a complete replacement of the original entry but a legally recognized update reflected through annotation.

9) Timing and delays: why it takes time

Even when everything is complete:

LCRO evaluation and processing takes time.
Transmittal to PSA and PSA database updating can take additional time.
The most common cause of delay is document inconsistency (spelling variations, different middle names, incorrect dates) or missing/unclear acknowledgment language.

A practical safeguard is to obtain:

A copy of the LCRO-received documents (stamped received)
Any LCRO endorsement/confirmation once processed
Then follow up by checking the PSA-issued copy later for the annotation

10) Common pitfalls and how to avoid them

A. The affidavits are notarized but incomplete

Common issues:

No clear statement that the father is acknowledging the child
Missing birth details
Wrong registry number or wrong LCRO details
Inconsistent signatures/IDs

B. The father’s details on the birth record don’t match the affidavit

If the father is not named on the birth record, or the record contains partial/incorrect paternal entries, the LCRO may require:

Additional supporting documents, or
A correction process before annotation can be properly reflected

C. Confusing “acknowledgment” with “legitimation”

Acknowledgment supports the child’s right to use the father’s surname (for illegitimate children) but does not, by itself, confer legitimacy.

D. Attempting to change a legitimate child’s surname by affidavit

This is a frequent mistake. Legitimate children’s surname issues are typically not handled by RA 9255 affidavits and often require judicial proceedings.

11) Special scenarios

A. Child was already registered using the father’s surname without proper basis

If the record shows the father’s surname but the supporting basis is missing or deficient, the LCRO may require curing documentation or formal correction depending on what is wrong with the entry.

B. Parents later marry: legitimation

If the parents were not married at birth but later marry, the child may be legitimated if legal requirements are met. This can involve:

Filing for legitimation annotation with the LCRO
Presenting the parents’ marriage certificate and other requirements
Updating the child’s status and potentially the name record through annotation

C. Mother wants the child to revert to her surname after using father’s surname

This is commonly treated as a substantial change with identity and record consequences. In practice, it often requires careful legal evaluation and, frequently, a court petition, especially if the change affects established identity and public records.

D. Father disputes paternity after acknowledging

If paternity becomes contested after acknowledgment, the matter is no longer a simple administrative update. Disputes over filiation are generally for judicial determination.

12) Practical checklist (quick reference)

Before filing:

Confirm the child is illegitimate and the request is to use the father’s surname under RA 9255
Ensure the father’s acknowledgment document is properly executed and notarized (or otherwise valid)
Ensure the AUSF is executed by the correct person (minor vs adult child)
Check consistency of all names, dates, and personal details

At filing:

Submit: birth record copy, acknowledgment document, AUSF, IDs, and any LCRO-required supporting documents
Obtain proof of filing/receiving

After filing:

Monitor LCRO endorsement/transmittal
Later request PSA birth certificate and verify the annotation

13) How to think about “PSA requirements”

The PSA does not usually “approve” the change at the counter the way a licensing office does. The typical workflow is:

LCRO processes and annotates / endorses based on the law and implementing rules
PSA updates its database upon receipt of official transmittal/endorsement
PSA issues the annotated certificate after posting

So, “PSA requirements” in this topic usually means:

The documents and standards the LCRO must accept and transmit in a form PSA can encode and reflect, and
The applicant’s need to obtain the PSA-issued annotated copy after the update is posted

14) Summary of the governing principle

In the Philippines, changing an illegitimate child’s surname to the father’s surname after an affidavit of paternity is generally handled through an administrative annotation process under RA 9255—typically requiring (1) valid acknowledgment of paternity and (2) an Affidavit to Use the Surname of the Father, filed with the LCRO and later reflected in PSA records through annotation. Cases involving legitimacy, disputes, or substantial identity corrections often move beyond affidavits and into court proceedings or more complex correction mechanisms.