If you wish to reuse or repurpose an ID in your group for a different user or customer, it is usually best to first delete that user and then activate a user. When activating an undefined user you can use the same ID as the one just deleted if you wish, but use a different password.

By deleting the user first all existing information such as Share Management and Address Book are also deleted, thus protecting that information from being seen by the new user. Of course this means information about any previous Shares is lost (though Shares themselves are not affected).

After deleting a user refresh the Group Administration display to see the additional Undefined User in your user list.

After activating the new user ID remember to set permissions for that user appropriately.