I recently asked for a day off 2 days in advance because my doctor had scheduled me for a CT scan. I work 12 hour night shifts in LTC. The scan was for the middle of the afternoon, and being anxious, I knew that I would get no sleep. My DNS told me that it wasn't an emergency and to reschedule it for my next day off because no one else could work for me!
I rescheduled it, I also spoke + cried with the adminisrator, who then spoke to the DNS who then apologized to me, but also stated that she still didn't see why I couldn't have worked that night.