You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Joseph Walker.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure.

ASSISTANT: Joseph, no reservation has been found on your name in our records.

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

ASSISTANT: Thank you for choosing us.