Is there a way I can remove/revoke WPMU credentials

Is there a way I can remove/revoke WPMU credentials from a site without being logged into it? For example, I'll be using Snapshot Pro to migrate from one server to another - but after I migrate, I won't be able to login to the original server. I'd like to be able to revoke access on that original WP deployment to my WPMU credentials.

Let me know if there is a way I can go about this! Thanks,

Jacob