Professionalism

I feel I'm a professional, but I don't know the nitty gritty details on how I should react in certain situations. And the problem with being a professional is that if I set standards, I can't let them slip even with my favorite student.

Let me give you an example.

No-shows: A no-show is where the student doesn't show up. It can also mean they didn't cancel within 24 hours. How do I differentiate between a student that overslept, a student that is on call and has to go perform surgery on short notice, and a photographer that forgot to cancel the flight? I'll never see the photographer again and who knows how I'll get paid (or if they will pay). The doctor student has a very valid excuse and warns me in advance if she is on call so I will have advance notice. The student that overslept should be billed (not my fault).

But as a professional I feel I should treat all these situations the same...