Modifications

The statute does not set a percentage for the change in income. It sets one for the change in support. Under RSMo § 452.370, if applying the child support guidelines to the parents’ current financial circumstances would change the existing support by twenty percent or more, that is a prima facie showing of changed circumstances substantial and continuing enough to modify — provided the existing amount was based on the presumed guideline amount.

So the first step in any support modification is a current Form 14. If the new number differs from the old by twenty percent or more, the burden shifts to the other parent to show why the order should not change. If it differs by less, the parent seeking modification has to prove a substantial and continuing change the ordinary way — a lasting change in income, a change in the parenting schedule, a change in the child’s needs — and the court considers all financial resources of both parties.

The condition matters. If the existing order was a negotiated number rather than a guideline number — parents who agreed to more, or less, than Form 14 — the shortcut is not available and the general standard applies.

Only to the date the other parent was personally served with the motion. RSMo § 452.370 provides that a support order may be modified only as to installments that accrued after the date of personal service. The court cannot reach back further, regardless of when the change actually happened or how good the reason for the delay was.

The corollary is that support which accrued at the old rate before service is a judgment. Each missed or underpaid installment is enforceable, with interest, through income withholding and every other collection tool, and it cannot be forgiven by the court on a later modification. A parent who stops paying because they lost their job, and files nothing, is building a debt the modification will not erase.

The practical rule is simple. When the change happens, file, and serve promptly. The date of service is the date relief begins.

A child’s preference is a factor, not a trigger. To modify custody under RSMo § 452.410 the court must first find a change in the circumstances of the child or the custodian, and then find that modification is necessary to serve the child’s best interests. An older child’s well-reasoned, sustained preference — particularly one tied to school, activities or a real problem in the other home — can be part of that showing. A twelve-year-old who would rather live where the rules are looser is not.

The court hears the preference carefully rather than casually. Under RSMo § 452.385 the judge may interview the child in chambers with counsel present and a record made. A guardian ad litem may be appointed under RSMo § 452.423 to report the child’s wishes. The statute also refers to the child’s input being “free of coercion and manipulation,” and evidence that a parent has been campaigning for the child’s vote tends to backfire.

It can be. A persistent refusal to follow the parenting plan — denied exchanges, unilateral schedule changes, cutting the other parent out of decisions — is a change in the circumstances of the custodian, and it goes directly to the RSMo § 452.375 factor asking which parent is more likely to allow the child frequent, continuing and meaningful contact with the other. Courts modify custody on this ground.

But modification is the slow remedy. The fast one is the family access motion under RSMo § 452.400, which the court must dispose of within sixty days and which can award make-up time, a fine of up to $500 payable to you, counseling, and attorney’s fees. Document everything as it happens — dates, times, what was said, in writing — and do not retaliate. RSMo § 452.365 provides that one parent’s failure to comply does not suspend the other parent’s obligation to pay support or permit visitation.

See visitation and enforcement for the family access motion in detail.

The presumption in RSMo § 452.375 is part of the best-interests analysis, and RSMo § 452.410 requires the court to find that modification is necessary to serve the child’s best interests. So once the threshold change in circumstances is shown, the presumption informs what the new arrangement should look like. It does not, by itself, supply the change in circumstances — the fact that the law changed in 2023 is not a change in the circumstances of your child.

In practice, a parent with an old every-other-weekend order who can show a real change — a move closer, a change in work schedule, a child who is now in school — is in a much stronger position than they were before 2023, because once the door is open, the statute now starts from equal time.

Yes. RSMo § 452.411 provides that if either parent changes residence to another state, that change of residence is deemed a change of circumstances under RSMo § 452.410, allowing the court to modify the custody decree. The relocation statute, RSMo § 452.377, separately allows the court to modify custody as part of a relocation proceeding, requires the court to allocate transportation costs and adjust support as appropriate, and treats a move without proper notice as a factor in modification.

Which court hears it is a separate question. The Missouri court that entered the order keeps exclusive, continuing jurisdiction under RSMo § 452.745 as long as the child or one parent still lives here. If everyone has left Missouri, the case belongs in the child’s new home state.

If the loss is involuntary and lasting, yes — and the sooner you file the better, because relief runs only from the date of service. An involuntary termination, a business failure, or a medical condition that reduces earning capacity are the classic substantial and continuing changes under RSMo § 452.370.

What the court will not do is reward a voluntary reduction in income. A parent who quits, takes a lower-paying job by choice, or declines available work can have income imputed at their earning capacity rather than their actual earnings, and the Form 14 runs on the imputed number. The court looks at work history, education, the local job market, and whether the change was made in good faith.

A short-term layoff is a harder case. “Continuing” means lasting; a parent who expects to be re-employed in three months is usually better served by an agreement with the other parent than by a motion the court may deny as premature.

Under RSMo § 452.340 support terminates when the child dies, marries, enters active military duty, becomes self-supporting, or reaches eighteen — unless the child is still in secondary school, or enrolls in a vocational or higher education program by the October 1 following graduation and completes at least twelve credit hours a semester, in which case support continues until the child completes the program or turns twenty-one. A child who works fifteen or more hours a week may carry nine hours. A child who fails half or more of the course load in a semester may lose eligibility. A child physically or mentally incapacitated from self-support may be supported indefinitely.

The college provision has a paperwork requirement that parents miss: the child must provide the paying parent with a transcript or enrollment documentation at the start of each semester, within thirty days of receiving grades. A parent who does not receive it may have grounds to stop paying.

Termination is often not automatic in practice. Income withholding continues until the order is changed, and the receiving parent has a statutory duty under RSMo § 452.370 to notify the payor of emancipation. Where the parties disagree about whether the child is emancipated, a motion to terminate or a motion to determine emancipation resolves it. The Missouri courts publish motion-to-modify forms for self-represented parents, though the interplay with withholding usually justifies counsel.

It depends on what the judgment says. RSMo § 452.335 requires every maintenance order to state whether it is modifiable or non-modifiable. A non-modifiable award cannot be changed by a later motion, however much circumstances have shifted — that certainty is what the parties bargained for. A modifiable award can be changed under the substantial-and-continuing standard in RSMo § 452.370.

Two further rules. A modifiable order with a termination date may be modified only on a substantial and continuing change that occurred before the termination date. And future maintenance ends on the death of either party or the remarriage of the recipient unless the agreement or judgment provides otherwise — an automatic termination that requires no motion, though the paying spouse should confirm it in writing.

You can agree to anything; the question is whether it is enforceable. An informal agreement to change the schedule or reduce support is not an order. If the other parent later changes their mind, the court enforces the written judgment, not the handshake — and a parent who paid less than the order required on an informal understanding still owes the difference, with interest.

The right way to do it is a stipulated modification: the parents sign an agreed motion, a new parenting plan and a Form 14, and the court enters a modified judgment. It is inexpensive, it is usually done without a hearing, and it protects both of you. Informal arrangements that work well are exactly the ones worth making official, because they prove the change is in the child’s best interests.

Respond, and respond on time. A proposed parenting plan is due within thirty days under RSMo § 452.310, and a parent who ignores a motion risks a default. The best defense is usually the statute itself: the other parent must prove a change in circumstances since the last order — on custody, one that makes modification necessary for the child; on support, one substantial and continuing enough to make the terms unreasonable. Many motions do not clear that bar.

The defense has its own evidence — the schedule as it has actually been followed, income records, school records showing the child is doing well. Where the motion is frivolous or brought to harass, RSMo § 452.355 allows the court to order the moving parent to pay your attorney’s fees after considering the merits and the actions of the parties.

Less than the original case, usually, because the issues are narrower — but it depends on whether the other parent contests it. An agreed modification can often be handled on a flat fee: the stipulated motion, the new parenting plan or Form 14, and the judgment. A contested modification is billed hourly against a retainer, with a written estimate and the assumptions behind it.

The costs outside the attorney’s fee are the same as in any family case: the filing fee, service, a guardian ad litem if custody is genuinely contested, and mediation if the court orders it. We tell you at the consultation whether the motion is likely to clear the statutory threshold, because a modification that cannot is not worth filing.