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.
(..) Okay. You okay? Just take a breath. Oh, God, sweetheart. It was an accident. It happens. I'll make the appointment. All you have to do is show up. For what? Three hours in the Emergency Room? All for nothing? All they did was rule out (..)2013 TvShow: Breaking Bad Title: Blood Money Season: 5 Episode 9