One of the parents must request that the court change the child support order, using a written "motion" a formal request to the court. List the child(ren)'s full name(s) and date(s) of birth.Line 2: Looking at the order, fill in the date, city or county where the order was granted, the case. On paper, filing for modification of a custody order is relatively easy. You are acting as good parent to your child may help in your modification case. Filing Motion to Modify Custody You will have to file a formal motion for modification with the same court where the custody order was issued. What Must You Prove To Modify A Custody Agreement In Maryland? I was wondering would be quicker to file a motion on my own at the court house or to fill out the modification form child support will send in the mail. What scenarios may qualify for a postdivorce modification in Maryland? Parties file motions to modify child support when a party experiences a significant change in income.