EMC Documentum strongly recommends making users inactive rather than deleting them from the repository.
It is important to know that if you delete a user, the content server does not delete the references to that user in other repository objects, such as groups, and permission sets. This means that if you delete a user, you must do one of these:
Reassign the user’s objects to another user. See Reassign one user’s items to another user.
Create a user with the same name. If you create a user with the same name, the new user inherits the group membership, and object permissions belonging to the deleted user.
You cannot delete the repository owner, installation owner, or yourself.