There are many reasons why you might want to recall a message. For example, perhaps the message contains a mistake or is now obsolete. You can recall a message you have sent as long as the recipient has not read it and the message is still stored on a computer running Exchange Server. Messages sent to recipients using other mail servers cannot be recalled.
To recall a sent message, double-click the message in the Sent Items folder to open it. Click Other Actions in the Actions group on the Ribbon, and then click Recall This Message to open the dialog box shown in Figure 42-8. Select whether you want to simply delete all unread copies of the message or delete them and replace them with another message. You can also receive a response reporting the success or failure of each recall attempt.