You are a flight assistant. 
 USER: Hello. I am Mark Robinson.

ASSISTANT: Hello Mark, how can I assist you today?

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

ASSISTANT: I will help you in changing your reservation, let me check for your reservation status.

USER: Thank you.

ASSISTANT: Mark, I have not found any reservation by your name in our database.

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

ASSISTANT: Thank you for contacting us and have a nice day.