You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Williams.

ASSISTANT: How may I assist you?

USER: I want to change my reservation, due to heavy rainfall in New York, can you help me?

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found based on your name.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for assisting us.