I have registered to take an online exam, and I need to go to a test center to take that exam. The question is, what's the appropriate way to talk naturally to the receptionist there and inform him or her about my reservation?
Hi, I have made a reservation for 8:30 to take xxx exam.
Hi, I have made a reservation to take xxx exam at 8:30.
Hi, I have an 8:30 reservation to take xxx exam.
In the above sentences, do you think it is better to change the word reservation to book?