Legal Question in Family Law in Louisiana

Re: How can I change my daugter last name?

You have to get her father's permission to do that. If he will not agree, then you will have trouble. If he has not seen or paid court ordered support, and he knew about his child, then why not have your husband adopt the child. Do an intrafamily adoption and if the father objects, you prove he has failed in his duty as a father and ask the court to allow the adoption without his consent.