Legal Question in Family Law in California

That's an amendment that requires a court order. A good place to start researching this is here:http://www.cdph.ca.gov/certlic/birthdeathmar/Documents/Affidavit-BirthPAMPHLET-(01-12)-MERGED.pdf

You say he is not the legal father. Is that something that has been determined in court? Unless and until there is a court determination that some other man is the father, or that the husband was sterile or otherwise could not be the biological father, the husband of a married woman is the legal father of children conceived during the marriage.

In essence the answer is that in order for you to get one name off the birth certificate, then you will have to replace it with another name. I would highly suggest you get competent family law counsel to help you with this. Good luck!