You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Williams.

ASSISTANT: How can I  help you?

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

ASSISTANT: Sure, just a moment please.

USER: Sure.

ASSISTANT: I am sorry no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.