1. Go to the Sent Items folder.

2. Open the message you wish to recall.

3. Click Actions–>Recall This Message.

To recall the message:

Select Delete unread copies of this message.
(Note: the recipient needs to have Outlook opened for the message to be deleted)

To replace the message:

Select Delete unread copies and replace with a new message, click OK, and type your new message.

To be notified about the success of the recall or replacement:

Check the Tell me if recall succeeds or fails for each recipient check box.