If you were divorced in Maryland, that is where the agreement needs to be modified. Ask in the Maryland forum
The law office of Anders Ferrington 601-316-8428 practices state wide. In no way am I offering you legal advice, and in no way has my comment created an attorney-client relationship. You are not to rely upon my note above in any way, but instead need to sit down with counsel and share all relevant facts before receiving fully-informed legal advice.