Changing a Child's Name: Changing My Child's Last Name when Father is Unknown

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

I'm trying to change my daughter's last name to my maiden name. The short of it is the father is unknown and there is no chance of finding who the father is, and there is no father on the birth certificate. I gave her the last name of the man I started dating and became engaged to while i was pregnant with her. Unfortunately things ended and now I am stuck trying to fix my mistakes. I've tried to contact him but he has completely disappeared.

Really my question is what do i need to do to get her name changed. Paperwork, process, the whole shebang.

Changing a Child's Name: Changing My Child's Last Name when Father is Unknown