We can add users to a departments by this list control.To access the option, the user has two alternative options. She can either select the department item by left click of the mouse button. The Manage user option is then listed as buttons on top of the list control.
User can also right click on the department and The Manage user option is then listed as the context menu.
The steps of this is detailed in the Navigation.
Note:If a user is admin of a particular department,then we can not remove him/her from user list