Rules for modifying a parenting plan must balance the benefits of stability against the costs of rigidity. On the one hand, changes in caretaking arrangements, or even the possibility that such changes will be made, promotes insecurity and instability in parenting arrangements. On the other hand, an inflexible approach to modification can perpetuate arrangements that have proven unsatisfactory or reduce a parent’s incentive to agree to modified arrangements that would benefit the child. Given the risks, no approach to this issue is without difficulty.
As a general rule, significant judicial modification of a permanent parenting plan is allowed only upon a showing of (1) a substantial change in the circumstances on which the parenting plan was based that makes modification necessary to the child’s welfare, excluding changes in economic or marital status, or in caretaking arrangements; or (2) harm to the child. In determining the reference point from which a change of circumstances exists, the usual rule is that the events must have occurred after the decree was entered and have been unanticipated by the parties. See, e.g., Lackey v. Fuller, 755 So. 2d 1083 (Miss. 2000) (mother’s pre-divorce extramarital affair should not be taken into account in action for modification) Modification is more readily available, under a less strict standard, in four specific circumstances: (1) changes agreed to by the parents, (2) changes in the actual arrangements under which the child has been receiving care without objection by the parent opposing the modification; (3) minor modifications in the plan; (4) the attainment of the age specified in a uniform rule of statewide application of a child who has a firm and reasonable preference for a different residential arrangement. Other special rules are designed to strike a balance between stability and flexibility in a child’s residential arrangements in the particular context of a parent’s relocation.