I'm assuming you're using Outlook. If you're working on an Exchange Server,
you might have luck with the Recall command. In the Sent Items folder, open
the message you want to retract. In the menu, choose Actions - Recall This
Message.
In Outlook open the sent folder, double-click the message to open it,
and then click Actions, and select Recall this message. You may or may
not be successful.