Changining a child's name requires the consent of BOTH parents.
If both parents do NOT agree, most judges just won't do it.
It's just easier to wait until the child is 18, then the child (now considered an adult) can do it without anyone else's consent. The adult needs to get a finger print card and fill out some paperwork. If the person does NOT have a criminal record and is NOT avoiding creditors, it's easy. Most judges are glad to do it.
The biggest pain is to to the SOCIAL SECURITY ADMINISTRATION office and then the TX Driver's License Office and get new identification.
The person will need to get all things changed -- passport, credit cards, etc.
It takes several weeks to get new id's issued.