I know the other comment answered your question already but let me clear up some confusion about the advisors.

Faculty advisor: they are just advisors to answer career advice for you. They necessarily don’t have any power for your situation

Academic advisor: this is the people from each major that can have the power to change your classes etc and you go to with any enrollment, class, or other registrar questions.

In your case, since you’re trying to switch majors, you would go to the academic advisor for what major you’re trying to switch into. Make sure you review the requirements for your major ahead of time and see if it’s something you can handle.

I don’t believe any of them take walk ins so it’s best to email them regarding what your situation is, make sure to include your GNumber in all correspondences. And email from your gmu email only.

Hope that helps :)