Step by Step:

If you and your recipients are all on Microsoft Exchange and in the same organization, you can recall or replace an email message that you sent.

Select File > Info.
Under Account Information, make sure the account you sent the email from is selected.
If your account is a Microsoft Exchange account and your email message recipients are all on the same email system, you can use recall or replace.
If your account is a MAPI or POP account, recall won't work.
Select the Back button .
In the navigation pane, select the Sent Items folder.
Double-click the email message that you want to recall or replace.
Select Message > Actions > Recall This Message.
Or, select File > Info > Resend or Recall > Recall This Message...
In the Recall This Message box, select an option:
1. Select Delete unread copies of this message to recall the sent message.
2. Select Delete unread copies and replace with a new message to replace the sent message with a new message.
Select the Tell me if recall succeeds or fails for each recipient check box.
Select OK.
NOTE: If you selected Delete unread copies and replace with a new message, the original message opens for editing. When you select Send, the original email message will be deleted from the recipient’s mailbox and replaced with the newly edited one.