To change your child support amount, you need an order from a judge or child support master — not just an informal agreement. Parents can agree to a new amount, but the court still has to approve it and find it serves the child’s best interest.
A court can modify support if there’s been a substantial change in your ability to pay, or if it’s been at least three years since the order was last set and the current guideline amount would differ by 20% or $100 from what you’re paying. Courts generally cannot retroactively reduce support you already owe — so if your circumstances change, report it and request a modification right away rather than waiting.