InfoPath Dev

Not sure I worded the title right but here is the issue we have.

We have a form that is emailed from SharePoint to 2 people. One of these 2 needs to click Approve or Disapprove and it updates the library status and sends out an email to a final approver. The final approver then approves or disapproves.

The problem is that they can reopen the email and change which one they clicked and hit submit again and it changes it in the library.

How can I stop the email from making a change after it has been submitted? 

Thank you!

Hi, we may not stop email or cancel email after one of 2 people Approve/Disapprove... Though, what we can do is -- add business process logic to avoid the issue.

Your form may already have 'Status' field, and we will use the status information 

Logics:

1. when  a person click Approve or Disapprove, change the State field value as "Approved" or  "Disapproved". Or you may set State as "Stage1" before the approval, and "Stage2" after the approval or something like that

2. for "Approved" and "Disapproved" button,  add Formatting Rules which hide the buttons if the form is already approved or disapproved using Status condition.

then the problem should be avoided, I think...