You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I will help you in changing the reservation. May I know your name please?

USER: My name is Kenneth Lee.

ASSISTANT: Sorry, there are no reservations found.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.