How to edit an email address on iOS

I mistyped someone's email, now I choose "Send again" But i can't edit their email address: backspacing selects the entire email and deletes all of it, tapping in the middle of the email selects all of it, and I can't even drag the cursor (force touch or hold space) into the middle of it How can I change an email address that is already entered in the "to" field