I'll add a few details, Rbuckman.

As of now, you'll want to follow the recommendation of AlexV since we're unable to control any edits happening in Outlook. You can set up Webmail instead.

On the other hand, you can reach out to Outlook support. They can assist you with editing the PO email.
 

We're available 24/7 if you have other concerns. Don't hesitate to reach out to us again. Take care!