Even after a custody order is in place, you and the other parent may agree to change your parenting arrangement. You'll need to submit your signed, written agreement to the court so that it can be put into a new court order. Judges usually approve parents' agreements as long as they appear to be in the children's best interests.
Without an agreement, you'll need to file a motion (an official request) to ask a judge to modify the existing order. Laws on child custody vary from state to state, including the rules for getting a custody modification. Typically, however, you’ll need to convince a judge that there has been a significant change in circumstances since the most recent order was issued, and that the proposed modification would be in the child’s best interests. Some states won't require proof of changed circumstances if you’re requesting only a change in parenting time (visitation), not where the child will primarily live. But you’ll still have to show that what you’re requesting would be best for the child.
A significant change means something more than a minor adjustment in your child’s school schedule or activities. A parent’s planned move is a common issue that often prompts requests for a custody modification. Although a long-distance move would count as a significant change in circumstances, most states have specific rules for dealing with child custody and relocation.
If your child’s other parent has been violating the existing custody order, you may return to court to ask a judge to enforce the order. Judges are reluctant to get involved with violations that can be irritating but are relatively minor—like being chronically late to pick up or drop off the kids. Most often, the judge will require the parents to go to mediation and try to work out the dispute. But if the violations are more severe, such as withholding visitation, the judge may hold the offending parent in contempt of court. Usually, the judge will start by ordering the parent to obey the orders and then will impose fines if the wrongdoing continues. In serious cases, custodial parents could lose custody altogether (if the other parent requests a modification based on the ongoing violations) or could face criminal charges for interference with custody.