Phrases Phrases for Making Reservations

I need a reservation.

Meaning

I require a booking.

John: Good evening. We'd like a table for dinner.
Alice: Certainly, sir. <b>I need a reservation</b> to check availability.
John: We don't have one. Could we possibly get a table?
Alice: Let me see... Unfortunately it's fully booked. <b>I need a reservation</b> for tonight. Do you have one?