You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am David Hill. I planned a trip to Denver but the trip is postponed, so I want to change my reservation.

ASSISTANT: Sure, please give me a minute.

USER: Ok.

ASSISTANT: David, there is no reservation available on your name.

USER: It's ok, thank you fro your information.

ASSISTANT: You are welcome.