You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you at this moment?

USER: I am planning to book a flight ticket to DEN from LAS, can you please help me out?

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

USER: Sure, my planned travelling dates are Dec 11 and Dec 13.

ASSISTANT: May I know your name for further process?

USER: Sure, my name is Kenneth Collins.

ASSISTANT: Is there any additional preferences do you have?

USER: I am looking for a direct flight.

ASSISTANT: Do you have any another specifications?

USER: I prefer economy class.

ASSISTANT: Ok, please hold on a moment.

USER: Ok, take your time.

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

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for reaching us.