Q-Eng

appointment：医者や弁護士などを含む「人」との面会予約
1. I have an appointment to meet Mr. Green.
2. I have an appointment with the dentist.
3. I have an appointment for a job interview at 11:30.
4. I'm sorry, I have another appointment.
cf.(Oxford 新英英辞典)
a formal arrangement to meet or visit somebody at a particular time, especially for a reason connected

with their work.
reservation：レストラン、ホテル、飛行機などの「場所」「部屋」「座席」の予約
1. I have a reservation at a hotel in Tokyo.
2. I have a rental reservation.
3. I'd like a room, but I don't have a reservation.
4. We have a dinner reservation for four people.
cf.(Oxford 新英英辞典)
an arrangement for a seat on a plane or train,a room in a hotel, etc. to be kept for you.