We are calling to 'confirm your appointment' with Dr. Jones. = We are calling to make sure that you will 'keep your appointment' with Dr. Jones.
The museum is open to visitors 'by appointment' only. [=you have to make an appointment to visit the museum]
The court ordered the 'appointment' of an attorney to represent the child.
(..) -CAT scan? No CAT scan. It's a transfer. It's a zoo transfer. Zoo transfer? Oh, no. No, no, I can't be transferred. I have an appointment with Dr Goldberg at . There are prescriptions that have to be filled. No other zoo could afford my medical care. (..)2005 Madagascar