Deleting principals from a database (Model Explorer)
To delete a principal:
1. Start Model Explorer.
2. In the left navigation pane, expand the SQL icon.
3. Expand the server that contains the database you want to delete a principal from.
4. Right-click on the database, point to Principals, then click Delete Principal....
5. In the Delete Principal dialog box, type a user or a group name in the following format:
◦ <domain\username> —to delete a user
◦ <domain\groupname> —to delete a group
6. Click OK to delete the principal from the database.
7. Confirm that the Principal deleted successfully message appears.