You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I best serve you now?

USER: I am Kevin Phillips. I want to change my existing reservation. Could you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no reservation found on your name.

USER: That's ok, no problem. Thank you for helping me.

ASSISTANT: Thanks for contacting us, have a great day.