How can I put my Father's Name on my birth Certificate?

Well here's the case:
-My BC says Unknown Father.

What do I need to do to get his name on my birth certificate? I would like to petition him as soon as I'm able to.

Please help.

have him sign an affidavit of acknowledgment and file at the civil registrar where the child was registered.

sir i also have a very big problem. Eversince i was a child and started my schooling, my father lets me used his surname. later i found out that in my original birth certificate, its just my mothers surname is indicated. He inserted his surname on my birthcertificate, Well admittedly its falsification. All the documents that i have shows my fathers surname. Unfortunately he died sir, i want to change my birth certificate to the one i am using right now. The problem is i only have letters and a gradeschool card with my fathers signature that proves he is acknowledging me. I lived with my father for almost 10years. He can no longer acknowledge me as his son because he is dead.Help me sir what to do, i have my fathers' sisters who can attest that I am acknowledged as his son. My father was absent when my birth certificate was created. Only my mother has affixed her signatue in the document so indeed i was marked as illegitimate son.

Sir with all due respect, i want to fix this problem, immediately. I want to legalized the complete name that i currently use, thank you. Hope to hear from you soon. God bless.

you can only establish your illegitimate filiation with your father during his lifetime. if you file a case to change your last name, i do not believe it will prosper. i suggest you revert to your mother's name.