You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today from my end?

USER: I would like to change my existing reservation, can you help me in that?

ASSISTANT: Sure, I am here to help you out. Please provide me your name in our database.

USER: Sure, myself Christopher Campbell.

ASSISTANT: Sorry Christopher Campbell, there is no flight reservation on your name in our database.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.