The Second Department noted that a court can modify child support without a substantial change of circumstances where a party’s income has increased by 15% or more and three years have passed since the last support order:
Section 451 of the Family Court Act allows a court to modify an order of child support, without requiring a party to allege or demonstrate a substantial change in circumstances, where (1) either party’s gross income has changed by 15% or more since the order was entered or modified, or (2) three years or more have passed since the order was entered, last modified, or adjusted (see Family Ct Act § 451[3][b][i]; Domestic Relations Law § 236[B][9][b][2][ii] …). The statutory grounds are not available in the event that the parties specifically opt out of that statutory provision in a validly executed stipulation (see Family Ct Act § 451[3][b]). In this case, the parties, in their stipulation, did not opt out of that statutory provision. Thus, the increase in the father’s gross income of more than 15% was sufficient, by itself, to permit the Family Court to modify his child support obligation … . .Matter of Regan v Regan, 2019 NY Slip Op 04702, Second Dept 6-12-19