"Reservation" 和 "appointment" 的用法很類似，但是並不一樣。

"Make a reservation" 通常是指你為自己預訂某些空間，
例如一張桌子（餐廳的座位）、一間飯店的房間、一個飛機上的位置等。

"Make an appointment"，則通常是指預約某人的時間，
例如上髮廊弄頭髮、和房屋仲介見面或看醫生等。

來看例句／對話：

Reservation

Restaurant : Hello. Smith’s Beach Bistro.
Kate : Hi, I have a reservation, and I was wondering if I could change the time.
Restaurant : OK. What’s your name?
Kate : Kim, Kate Kim. The reservation is for five people at 5:30 tonight.
Restaurant : Yes, Ms. Kim. What time would you like to change your reservation to?
Kate : Could you change it to 6:30, please?

Appointment

I’m going to be late for our appointment. I’m sorry, but I can’t get to your office by 1:30.
我會遲到一些。很抱歉，我一點半之前趕不到你的辦公室。