Project > View Envelopes > Choose recipient > Action > Revoke
Go to your Project and click View Envelopes. It will pull up a list of the envelopes that have been sent. Find the name of the recipient for whom you will revoke an envelope. On the far right of your screen you will see the Actions button. This will pull up the Revoke button.
Project Tile > # of Envelopes Sent > Find Recipient > Action > Revoke
You can also click the number of envelopes on the Project Tile and this will take you to the same report. Click Action, then Revoke.