You can only do this if both you and the recipient are using Microsoft
Exchange, and only under very specific conditions. If you are using Outlook
to access a standard ISP mail account, then no you cannot.
Open the email that you have sent that you wish to recall. Click on Actions,
scroll to Recall this message. You will then be given the option to delete
the message or delete it and replace it with a new one. Even on the same
Exchange server this may or may not work.