It can happen, you sendt something. Know that if the user opened the mail, you can not do anything about it. However if your mail has not been read you can recall it.

Anyhow, just try this:

 

call-back-mail
Ops, should I have sendt that?
mail
Open the mail

 

 

recall
Click file and click the “Recall button”

 

 

recall-button-step-2
You can recall and replace if needed
recall-option-outlook
Delete messages and/or replace them with a new one?