Open Outlook and go to the Sent Items folder
Double-click the email you want to rescind
Select File
Choose Info
Click Message Resend and Recall
Select Recall This Message
Choose Delete unread copies of this message or Delete unread copies and replace with a new message
Optionally check Tell me if recall succeeds or fails for each recipient
Click OK
If replacing the message, make your changes and send the updated email
Make sure the recipient uses Microsoft Outlook and has not already read the message
Note that recall works best within the same organization and Exchange or Microsoft 365 environment