Change surname from my Filipina mother's name to my Japanese dad's name

Hello everyone,

I need your help. I am already of legal age, and I've been working here in the Philippines for more than 10 years already. I am using my mom's last name. But I want/need it changed to my dad's. On my birth certificate, which is registered late, my mom and dad have their signatures in it, but what's reflected there as my surname is my mom's surname, and that's what I've been using ever since. By the way, THEY AREN'T married

May I ask what's the process in changing my surname from my mom's last name to my dad's last name? And by change, I do mean completely changing my last name, not just on my birth certificate, but on everything. I want the court to accept my wanting to change my last name to my dad's. This means that my surname on my passport would have to be changed as well, my SSS ID, my Pag-ibig, Philhealth, etc.

By the way, my dad is already dead. He already has had another family in Japan, but I am listed on their kosekitohon (or their family tree in there). Also, I've had DNA test and it's 100% that he is my father.

May I also ask how long it will possibly take and how much will I be spending to have this changed?

Thanks in advance!


Regards,
The Idealist