You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian Collins.

ASSISTANT: How can I aid you today?

USER: I want to book a ticket from DEN to LAX to attend seminar, can you help me in booking?

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

USER: I am departing on Oct 29 and return on Oct 31.

ASSISTANT: Do you have any preferences regarding timings of your journey?

USER: I want to depart in afternoon.

ASSISTANT: Are you okay with connecting flight or you need any direct flight?

USER: I need a direct flight.

ASSISTANT: Is there any additional preferences do you have?

USER: I need a flight with economy class.

ASSISTANT: Ok, please wait a moment.

USER: Sure, take your time.

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

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.