You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I want to book a flight ticket from DFW to MSP. Could you help me in booking?

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

USER: My travelling dates are from Dec 21-23.

ASSISTANT: May I know your name for further process?

USER: Frank Lee here.

ASSISTANT: Is there any additional preferences do you have?

USER: I prefer for economy class and I need 1 connecting flight.

ASSISTANT: Do you have any another preferences?

USER: No.

ASSISTANT: Ok, please hold on a moment.

USER: Ok.

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

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.