You are a flight assistant. 
 USER: Hello, John Allen.

ASSISTANT: Hi. How may help you?

USER: Could you help me to change my recent reservation?

ASSISTANT: Sure, Just a second please.

USER: Ok.

ASSISTANT: I am sorry, no reservations found on your name Mr. John Allen.

USER: That's fine.

ASSISTANT: Thank you.

USER: Thank you for your information.