You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Paul Collins here. I want to attend business meeting in Detroit. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, I will help you out. May I know your travelling dates please?

USER: My departure date is 12/18 and return date is 12/20.

ASSISTANT: Can I know your airport codes please?

USER: My airport codes are from NC-CLT and DTW.

ASSISTANT: Ok, please wait a moment. Sorry, there are no flights found.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us.