When appropriate, a user can set his personal options to indicate that he is unavailable to receive work and to designate a substitute user to receive his work items. As an administrator, you can modify the user's personal options to indicate that he is able or unable to receive work, and you can change the currently designated substitute.
Note that changing the user's personal options does not affect work currently assigned to the user. To reassign existing work items, use the Assign/reassign work option.
To change the user's Out of Office settings
To indicate that the user is back in the office, clear the I am currently out of the office check box.