Changing the Primary Department for an Agent

Hi,

I'd like to change the primary department for an agent from the default one to one I recently created. I go to the Agents tab, click on their name, and change the department in the drop down box, but when I try to save it won't let me since "the passwords don't match".  I do not know her password, nor do I want to reset it.  Is there any way to change her department as an admin, or will she need to log in and change it in her own account?