Site dropdown is grayed out for admins in Virtual Office Configuration Manager:
Changing the site of a user is currently not supported in Virtual Office Configuration Manager.
Currently, the only way to change the site of a user is to first delete the user and then recreate the user with the desired site. This is due to a limitation in the backend systems of the Configuration Manager. We hope this to get this limitation figured out as soon as possible but don't have an ETA at this time.