Open Outlook and go to Sent Items
Double-click the email you want to recall
In the Message tab, select Actions
Click Recall This Message
Choose Delete unread copies of this message or Delete unread copies and replace with a new message
Optionally select Tell me if recall succeeds or fails for each recipient
Click OK
If replacing the message, edit and resend the updated email
Note that recall works only if both you and the recipient use Microsoft Exchange or Microsoft 365 in the same organization
Note that recall may fail if the recipient has already opened the email or uses a different email system