How do I let an admin for a site log back in via my Elite account, when she made the mistake of crea

An admin who works on one of my sites was newly logging into WPMU Dev, and forgot that she should have logged in via my account. Instead she created a new account, with a new API key, and now she can't access the site I need her to be able to access. She has deleted her WPMU Dev Dashboard plugin, and reinstalled it, but it still recognizes her and won't let her log in via my account.

Any thoughts? Thanks!