455.530. 1. Provisions of any order respecting maintenanceor support may be modified only as to installments occurringsubsequent to the motion for modification and only upon a showingof changed circumstances so substantial and continuing as to makethe terms unreasonable.
2. Provisions of any order respecting custody may bemodified only if the court finds, upon the basis of facts thathave arisen since the prior order or that were unknown to thecourt at the time of the prior order, that a change has occurredin the circumstances of the child or his custodian and that themodification is necessary to serve the best interests of thechild.
3. Provisions of any order respecting visitation may bemodified when the modification would serve the best interests ofthe child.
(L. 1987 H.B. 598 ยง 13)