Perform the following steps:
Choose Tools -> Settings.
Click Out of Office in the left pane.
To specify that you are unavailable, select the I am currently out of the office option.
To specify that you are available, select the I am currently in the office option.
Type your out-of-office message in the Out of Office Message text area.
If you select the I am currently out of the office
option, the next time that you log in to your
account, an Out of Office Assistant dialog is displayed.
The dialog asks if you want to change your status from unavailable to available.
To change your status to available, click on the Yes, Change Status button. To leave your status unchanged, click on the No, Don't Change Status button.