Question:   How can we change the custody arrangement set out in the existing custody order?

Answer: The name of the action to take in this situation is a Motion to Modify, which is necessary to change the custody arrangement and the child support. The Texas Family Code provides that a child may sign an affidavit of choice of conservator at the age of twelve. This is only one piece of evidence, and the court will still determine what is in the best interest of the child. Of course it becomes a bigger piece of evidence the older the child gets.