awww, I did that once. The response wasn't great because I woke up right when the appointment was supposed to start, and called, and said that I couldn't make it. And my T didn't know that I didn't have a car, and got mad because she thought I could just drive over there and be a little late. Well it turned out that she wasn't a very good T so I expect that a good T would be understanding. Maybe you can go latter in the week if she has space?