You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian Lewis.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation, due to heavy rainfall in Seattle.

ASSISTANT: Sure Lewis, please wait a moment. Sorry, there is no reservation found on your name.

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

ASSISTANT: Thank you for approaching us.