Cal. FAM § 7575

(a) Either parent may rescind the voluntary declaration of parentage by filing a rescission form with the Department of Child Support Services within 60 days of the date of execution of the declaration by the attesting parents, whichever signature is later, unless a court order for custody, visitation, or child support has been entered in an action in which the signatory seeking to rescind was a party. The Department of Child Support Services shall develop a form to be used by parents to rescind the declaration of parentage and instructions on how to complete and file the rescission with the Department of Child Support Services. The form shall include a declaration under penalty of perjury completed by the person filing the rescission form that certifies that a copy of the rescission form was sent by any form of mail requiring a return receipt to the other person who signed the voluntary declaration of parentage. A copy of the return receipt shall be attached to the rescission form when filed with the Department of Child Support Services. The form and instructions shall be written in simple, easy to understand language and shall be made available at the local family support office and the office of local registrar of births and deaths. The department shall, upon written request, provide to a court or commissioner a copy of any rescission form filed with the department that is relevant to proceedings before the court or commissioner.

(b) This section shall become operative on January 1, 2020.