How do you create an approve and reject button within Email Notifications?

I have another followup to this. If a user initially approves the file, then goes back in and decides to reject, the "Waiting on Approval From" field does not show that user because they have initially approved it. Is there any way to change this logic?  

Also, lets say a user rejects a file.  A new revision of the file is uploaded. Is there a way to reset the approval process?  
I'm thinking my solution/work around would maybe be another new set of approval fields, ie Document Approval Rev 1, Document Approval Rev 2, Document Approval Rev 3. 


Thank you!