You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Carol Evans.

ASSISTANT: How can I assist you?

USER: My business meeting has been postponed.So, I would like to change my existing reservation. Can you please help me with that?

ASSISTANT: Sure, give me a moment.

USER: Sure.

ASSISTANT: Sorry Carol, there is no flight found with your requirements.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.

ASSISTANT: Have a nice day.

USER: Thank you.