If there is an instance in which you would like to prevent a specific recipient from receiving a flow email, you can cancel the email for just that one person.
Cancel a Flow Email for a Single Recipient
To do this, navigate to the flow email you would like to cancel. Click View all Analytics.
Here, find the recipient you would like to cancel the email for, and click Cancel on the far right. You can cancel recipients who are in either the Waiting or Needs Review tab.