In many but not all divorce cases, there exists a Judgment or an order that a spouse pay another spouse child support, spousal support or both. Orders are enforceable the same way Judgments are. The question is how do these orders get modified? There are two ways only. They are: 1) File a Request for Orders in Court and appear and have the Court make the order or 2) See if your ex will sign a stipulation and order modifying the order. Those are the only two ways. The first way is rather simple, namely seek a Court order and have the Court make the order. Simplicity does not mean that it is easy however. You must find the right forms to fill out, draft a declaration setting forth admissible evidence, and have it properly filed and served. Next, you must deal with the Response and likely opposition. You will then need to be prepared to answer the Court's questions. Then, if your motion has merit, you will likely obtain the modification you seek.
The second way is much more problematic. To modify an order, you need to present another order. So, if your ex is agreeable, you need to draft a Stipulation and Order and have the Court sign off on it. Seems simple? It is. Too many people mess this one up. I have seen agreements drafted on restaurant napkins, newspapers and envelopes. None of these has the legal effect of modifying a valid court order and none of these will stand up to judicial scrutiny.
So, here it is: You can only modify a support order with another support order. You can obtain the order by asking the Court for it. You can also present a stipulated (agreed upon) order to the Court for execution. Save the restaurant napkins for the restaurant.