Child Protective Services.
They won't change the child's name. The will, instead, help an abused child.
The minor won't be able to change his/her name just to get back at his/her parents until he/she turns 18 without the written consent of both parents.
This sounds a bit like a child throwing a tantrum and saying, "I don't want anything to do with you (parents)!!!! I will show you by changing my name!!!)

