You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you for the day?

USER: Christopher Harris here. I would like to change my existing reservation, because my project seminar was postponed.

ASSISTANT: Christopher Harris, can you wait till I check your previous reservation?

USER: Sure.

ASSISTANT: Sorry to tell you, no reservation found by your name. Thanks for reaching us.

USER: Ok, that's fine.

ASSISTANT: Have a great day.

USER: Thank you for your services.

ASSISTANT: You are welcome.