In the Philippine legal system, the naming of children is governed by the Civil Code, the Family Code, and subsequent amending laws like Republic Act No. 9255. Historically, the law leaned heavily toward patriarchal traditions, but recent jurisprudence and legislative updates have expanded the rights of children and mothers to choose the mother's maiden name.

1. The Legal Status of the Child

The requirements and procedures for changing a surname depend heavily on whether the child is classified as legitimate or illegitimate.

Legitimate Children: Under Article 174 of the Family Code, legitimate children shall principally use the surname of the father. However, recent Supreme Court rulings (notably Alanis III v. Court of Appeals) have clarified that "principally" does not mean "exclusively."
Illegitimate Children: Under Article 176, illegitimate children shall use the surname and shall be under the parental authority of their mother. They may use the father's surname only if the father provides an Affidavit of Admission of Paternity or a private handwritten instrument.

2. Grounds for Changing a Surname

Changing a name is a privilege, not a right. The petitioner must provide "compelling reasons" to the court. Common grounds recognized in Philippine jurisprudence include:

Avoidance of Confusion: When the current name causes confusion in school, government records, or social circles.
Embarrassment or Slander: When the father’s surname is associated with dishonor or causes the child social stigma.
Consistency with Identity: When the child has been known by the mother's maiden name since infancy and switching would be detrimental to their identity.
Preference for Maternal Heritage: Following the landmark Alanis III ruling, the court acknowledged the constitutional right to gender equality, stating that a legitimate child can choose to use the mother's maiden name as their primary surname.

3. The Judicial Process (Rule 103)

A substantial change of name (such as changing a surname) generally requires a Judicial Petition under Rule 103 of the Rules of Court.

A. Where to File

The petition must be filed in the Regional Trial Court (RTC) of the province where the person whose name is to be changed resides.

B. The Petition Requirements

The petition must be verified and set forth:

That the petitioner has been a resident of the province for at least three (3) years prior to filing.
The cause or reason for the change of name.
The name sought to be adopted (the mother’s maiden name).

C. The "In Rem" Nature of the Case

This is a proceeding in rem, meaning it is a strictly public matter. The court will issue an Order of Publication. This order must be published in a newspaper of general circulation once a week for three consecutive weeks. This notifies the public and the Solicitor General, allowing any interested party to file an opposition.

4. Administrative vs. Judicial Changes

It is vital to distinguish between a change of name under RA 9048 (as amended by RA 10172) and Rule 103.

RA 9048 (Administrative): This is handled by the Local Civil Registrar. It is only for correcting clerical or typographical errors (e.g., "Smyth" to "Smith") or changing a first name.
Rule 103 (Judicial): This is required for substantial changes, such as changing the surname to the mother’s maiden name. A Local Civil Registrar does not have the authority to change a surname based on preference or status changes.

5. Essential Documentary Requirements

When filing the petition, the following documents are typically required:

PSA Birth Certificate: The original copy showing the current registered name.
Baptismal Certificate: Or other school/employment records showing the child's consistent use of the desired name.
Affidavits of Witnesses: Two disinterested persons who can vouch for the child's identity and the reason for the change.
NBI, Police, and Court Clearances: To ensure the name change is not being used to evade criminal liability or civil obligations.

6. The "Alanis III" Precedent (2020)

In the case of Alanis III v. Court of Appeals (G.R. No. 216425), the Supreme Court ruled that a person can use their mother’s maiden name as their surname even if they are a legitimate child. The court emphasized:

"The law does not say that legitimate children cannot use their mother’s surname. It only states that they shall principally use the father’s surname."

This ruling is a significant shift, as it moves away from the strict requirement of proving "dishonor" or "confusion" and leans toward the child's right to self-identification and gender equality between parents.

7. Effects of the Change

Once the court grants the petition, the judgment is served to the Local Civil Registrar where the birth was recorded. A marginal annotation will be made on the original birth certificate. The old surname is not erased; rather, the record is updated to reflect the new legal name. All subsequent official documents (Passport, ID, etc.) will then be issued under the mother's maiden name.