You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Davis.

ASSISTANT: Nancy, how can I assist you?

USER: My business meeting has postponed, so I want to change my existing reservation. Can you please help me with that?

ASSISTANT: Sorry, no reservation found by your name.

USER: That's ok.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your time.