To retrieve an email message that has been sent, follow these steps:

1.  Open the Sent Email Folder.
2.  Open the Email Message you want to recall.
3.  Click on Actions located on the top menu bar.
4.  Select Recall Message.      

You will have an option to delete the message or to delete and replace with a different email message.  If you want to be notified that this action was successful, be sure to check the option Tell me if recall succeeds or fails for each recipient.