Montana Mont. LBF 19-A. MOTION TO MODIFY PLAN [MONT. LB] is a legal document used to seek modification of the Montana Revised Uniform Child Support Order. It is primarily used when parents involved in a child support order want to modify the amount of support payments, the payment schedule, or both. The Montana Mont. LBF 19-A. MOTION TO MODIFY PLAN [MONT. LB] includes two types of motions: an original motion and a motion to modify. The original motion is used to request a modification for the first time, while the motion to modify is used to modify an existing order. Both types of motions require detailed information, such as the parties involved, the current order, the proposed changes, and the reasons for the modification.