Open Outlook and go to Sent Items
Double-click the email you want to retract
In the Message tab, select Actions
Choose Recall This Message
Select Delete unread copies of this message or Delete unread copies and replace with a new message
Check Tell me if recall succeeds or fails for each recipient if needed
Click OK
Wait for the recall status notification
Note that recall works only in certain Microsoft Exchange or Microsoft 365 environments
Note that recall usually works only if the recipient has not read the message
Note that recall may fail if the recipient uses a different email system or has rules that move the message