You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Andrew Lee. Can you help me in changing my previous reservation?

ASSISTANT: Sure, I will help you out.

USER: OK.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there are no reservations found on this name.

USER: That's fine. Anyway, than you for your help.

ASSISTANT: Thank you for reaching us.