What are the rules for reducing child support in NY state?

You would have to consult a lawyer and since EVERY decree of divorce is different you really can't compare HIS child support to the one your ex pays. Or that YOU have never bothered to ask for a raise in it when you ex got a raise. That to me only means that you don't think your child deseves to be supported as much as his ex wife thinks THEIR child needs to be supported.