Open Outlook (desktop app)
Go to the Sent Items folder
Open the email you want to recall
Select the Message tab
Click Actions
Select Recall This Message
Choose one:
Delete unread copies of this message
Delete unread copies and replace with a new message
(Optional) Edit the replacement message, then send it
Click OK to send the recall request
If prompted, select the appropriate options for your account/environment
Note: Recall works only if the recipient’s mailbox supports it and the message is still unread