A: Trip dot cons. How can I help you?
B: I'd like to change my reservation.
A: May I have your reservation number?
B: It is 6454. 1 made a reservation yesterday.
A: It's under Mr. Clarke's name, two tickets to London. What do you want to change, sir?
B: It's supposed to leave in the morning according to the reservation, right?
A: Correct.
B: Something has come up and I have to change the leaving time. Is there a later flight?
A: I'm afraid we have only one flight for London each day.
B: Does it mean that I can't change the leaving time?
A: I'm sorry. Anything else I can do for you, sir?
B: Yes, I want to book an extra ticket.
A: OK, one ticket for?
B: London.
A: OK, sir. Wait a second.
(15 seconds later)
A: Sorry, sir. The economy seats are fully booked. Can you reserve a first class seat?
B: It's OK.
A: Your reservation has been made.
B: Thanks, bye.