You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. In which way I can aid you at this moment?

USER: I am searching an economy class flight to reach Charlotte, can you please find a flight for me?

ASSISTANT: Sure, I will aid you with that. Can you please mention your preferable travel dates?

USER: Thank you. I prefer to travel on the dates of Nov 11 and Nov 13.

ASSISTANT: May I know your preferable airport code names?

USER: The source and destination airport codes are OAK and CLT.

ASSISTANT: May I know your name for further process?

USER: My name is Mark Campbell.

ASSISTANT: Do you have any another specifications?

USER: Just now I have concern about the economy class, so please search the flight with business class.

ASSISTANT: Ok, please hold on a moment.

USER: Ok, take your time. I need a return flight in the evening time.

ASSISTANT: Ok. Sorry, no flights are available in this route as per your requested dates.

USER: It's ok, not a problem with that. Thank you for your time.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.