The idea is to be able to close (block off) a day in your calendar with different status (Ex: Hospital, Vacation, Unavailable, Meeting...) without putting in an appointment to fill the space. That way, when you use the MD button you will actually see who's working and not the doctors that blocked their calendars with a fake appointment.
It would have to be different color (or pattern) so that when you look at the monthly view, you can differentiate appointments (pink) from day offs (eg: vacation, hospital, unavailable). Each different status needs to be a different color (or pattern) because, the admin needs to know easily when the doctors are at the hospital vs vacation vs unavailable. It's basically the same as the google calendar when you choose the "out of office" status. The admin can then easily see with the monthly view if some offices are available or not in the clinic.
We should be able to click on the top of the calendar (beside the doctors name) to block the whole day off or, be able to do it for a chosen period of time. The color could be really pale or even translucent.