My question involves name change laws in the State of: Florida

My friend is wondering if she would have to contact the bio-father or not in this instance. She got pregnant, bio-father kicked her out. Paternity was established (via court order to receive medical treatment, although no name on birth cert) but mother waived any necessary support as she had a fiancé already. Mother wanted nothing to do with bio-father and bio-father wanted nothing to do with them. It's now been over 15+ years (friend is married to said fiancé) but they want to change the son's name to match theirs. She has no whereabouts of bio-father and doesn't want any contact with him. She heard of a petition to the court but cant find anything in all the statutes. I'm just trying to help her out...ANY help would be greatly appreciated. Thanks! (even links to specific statutes would help as well)