You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Christopher Wright. Can you help me in changing the existing reservation?

ASSISTANT: Sure, give me a moment to check the details.

USER: Ok.

ASSISTANT: Sorry Wright, there is no reservation available on your name.

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

ASSISTANT: You are most welcome.