You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Andrew Wilson. I want to change my existing reservation, because workshop in New York is postponed.

ASSISTANT: Sure, please give me a minute.

USER: Ok.

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

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

ASSISTANT: You are welcome.