Prevent reopening service appointments

Sometimes users keep a Power Lane open for a long time. Here's how this plays out.

Joe opens his 11 AM appointment in Power Lane and leaves that open on his tablet. Meanwhile, he converts the appointment to a work order either from Q DMS, or from another computer.

Joe gets back to his tablet and remembers there was something he needed to update, like the license plate number. He updates that on his tablet, then goes back to the Power Lane appointment screen.

Now, Joe still sees the 11 AM appointment. This is because he reopened it on accident, by keeping that original appointment open and making changes to it after it was already converted.

I would like some functionality to prevent these appointments from reopening.