Rather, the spouse must wait until the change happens and then petition for modification. (hildebrandlaw.com)
To get the ball rolling, you must file a Supplemental Petition for Modification of Child Support. (familydiplomacy.com)
To seek a modification of your child support order, either for an increase or reduction, you must file Form 12.905 (b), Supplemental Petition for Modification of Child Support, with the jurisdiction where the original child support order was made. (info.legalzoom.com)