How to Manage Physician and APP Cancelled Shifts

On the surface, it may appear that a cancelled shifts is a simple concept.  Someone is unable to work, so their shift ends up being cancelled.  When one considers this a little further, it becomes clear that this is more complex.  With respect to required shift tallies, are there circumstances where a shift may count towards required shift tallies?  How are cancelled shifts tracked, and who is responsible for that?  Does a scheduling system [...]