Dumb decision - Childs last name

The father of my daughter was never in her life until she was 3 years old. We went to court for a child support since I was always sick in the hospital and they tracked him down to help me support her since they had put me and her on medicate. We were good friends, but just went seperate ways and stupid me decided to allow him to have the last name on the birth certificate. I thought my daughter would be happy since the short time she saw him, she was very very happy! She took him in like he was always there. Now he is out of her life again after so many empty promises to her... She is stuck with his last name or is there a way to change it back? I told her about her last name (she is 4 now) and she doesn't like it. She want's her old name back. I don't want to make her upset and if I would have known she wanted to keep my name.. I would have left it at that. Stupid me felt for the "if im going to pay child support I want her to carry my last name at least" ... and since im TOO damn nice... I let it be changed... Is there ANY WAY that this can be undone? I don't want her to be unhappy =[.

Thank you.

[judg4]

You can file to change it back but in some locations he may need to consent or you at least have to swear he cannot be located.