I have to move several hundred of user mailboxes from exchange server A to exchange server B. Both servers have all roles installed and both will be kept online afterwards. Is there a way I don't have to change the incoming/outgoing server settings (from Server A to Server B) in their outlook clients so that disruption to users can be minimized? Also, is there a way users can still use the old url to get access to their mailboxes via owa? Thanks