Think through what you want to ask, have notes in front of you if needed, take a deep breath, and try out the 20th c. technology of a telephone call. There should be a number on the MOC website.
If there is a recorded directory answer, hope for "Service Academy affairs" or similar option. If not, wait for the "other matters" or similar option to get to a live person.
"Hello, I'm Name. May I speak with someone who works with Sevice Academy nominations?" Once you're with the right staffer, express appreciation for the West Point nom, share that you also have an active application for USMMA, and would like to inquire if there is a possibility of ...
As I understand it, ANY MOC in your state can give a nom to USMMA. Time to start working the websites and phones. Before charging down that path, confirm with a primary source, USMMA website.
Presenting yourself well and communicating effectively on the phone are skills very much required of a successful officer. Time to practice!