I’d used some Sick Leave for the time off from work today for a dentist appointment, but I got a call this morning that he wasn’t feeling well and that they would call back later to reschedule.

Should I call my work to let them know I'm available after all? And if I'm not needed, should I change my leave request to Annual Leave instead of Sick Leave?

In this case, I called my work to let them know I was available after all, but I'm wondering what the proper etiquette for this kind of situation is.