In Course Navigation, click the People link.
In the search field [1], search for the name of the user. You can also filter users by role in the Roles drop-down menu [2].
Click the user's Options icon [1], then select the Deactivate User link [2].
Click the OK button.
If you want to re-activate the user at a later time, click the user's Options icon [1], then select the Re-activate User link [2].