Cal. Civ. Proc. Code § 1276

(a)
1. (1) All applications for change of names shall be made to the superior court of the county where the person whose name is proposed to be changed resides, except as specified in subdivision (e) or (g), either (A) by petition signed by the person or, if the person is under 18 years of age, by one of the person’s parents, by any guardian of the person, or as specified in subdivision (e), or, if both parents are deceased and there is no guardian of the person, then by some near relative or friend of the person, or (B) as provided in Section 7638 of the Family Code.
2. (2) The petition or pleading shall specify the place of birth and residence of the person, the person’s present name, the name proposed, and the reason for the change of name.
(b) In a proceeding for a change of name commenced by the filing of a petition, if the person whose name is to be changed is under 18 years of age, the petition shall, if neither parent of the person has signed the petition, name, as far as known to the person proposing the name change, the parents of the person and their place of residence, if living, or, if neither parent is living, near relatives of the person, and their place of residence.
(c) In a proceeding for a change of name commenced by the filing of a petition, if the person whose name is proposed to be changed is under 18 years of age and the petition is signed by only one parent, the petition shall specify the address, if known, of the other parent if living. If the petition is signed by a guardian, the petition shall specify the name and address, if known, of the parent or parents, if living, or the grandparents, if the addresses of both parents are unknown or if both parents are deceased, of the person whose name is proposed to be changed.
(d) In a proceeding for a change of name commenced by the filing of a petition, if the person whose name is proposed to be changed is 12 years of age or older, has been relinquished to an adoption agency by the person’s parent or parents, and has not been legally adopted, the petition shall be signed by the person and the adoption agency to which the person was relinquished. The near relatives of the person and their place of residence shall not be included in the petition unless they are known to the person whose name is proposed to be changed.
(e) All petitions for the change of the name of a minor submitted by a guardian appointed by the juvenile court or the probate court, by a court-appointed dependency attorney appointed as guardian ad litem pursuant to rules adopted under Section 326.5 of the Welfare and Institutions Code, or by an attorney for a minor who is alleged or adjudged to be a person described in Section 601 or 602 of the Welfare and Institutions Code shall be made in the court having jurisdiction over the minor. All petitions for the change of name of a nonminor dependent may be made in the juvenile court.
(f) If the petition is signed by a guardian, the petition shall specify relevant information regarding the guardianship, the likelihood that the child will remain under the guardian’s care until the child reaches the age of majority, and information suggesting that the child will not likely be returned to the custody of the child’s parents.
(g)
1. (1) On or after January 1, 2023, an application for a change of name may be made to a superior court for a person whose name is proposed to be changed, even if the person does not reside within the State of California, if the person is seeking to change their name on at least one of the following documents:
  1. (A) A birth certificate that was issued within this state to the person whose name is proposed to be changed.
  2. (B) A birth certificate that was issued within this state to the legal child of the person whose name is proposed to be changed.
  3. (C) A marriage license and certificate or a confidential marriage license and certificate that was issued within this state to the person whose name is proposed to be changed.
2. (2) For the purposes of this subdivision, the superior court in the county where the birth under subparagraph (A) or (B) of paragraph (1) occurred or marriage under subparagraph (C) of paragraph (1) was entered shall be a proper venue for the proceeding. The name change shall be adjudicated in accordance with California law.