If you are an administrator, you can log off a user from a session (for example, if the user has an session has crashed) in Remote Desktop Services Manager by using the Log Off action.
Follow these steps to log the user off:
In Remote Desktop Services Manager, on the left pane, click the Remote Desktop Session Host server on which the user session is running.
On the Users tab, right-click the user that you want to log off, and then click Log Off.
Click OK to log off the user from the session.
and that's it.