Open Outlook
Go to Sent Items
Double-click the sent email to open it
Select File
Click Info
Click Resend or Recall
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
If replacing, edit the message and send it again
Note that recall works only in certain Microsoft 365 or Exchange accounts
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 already opened the email