Work with your lawyer to persuade the court how the change will benefit the child: Prepare to demonstrate to the judge how your proposed modification to child support benefits your child. Usually, a change on its own won't suffice to justify a modification in child support.
In your letter, you must identify who you are, state specifically what your change in circumstance is, and definitively request a review of your case. You will send this letter to the CSE caseworker assigned to your case in the regional office that enforces your order. You can find that information on the CSE website.