You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: Can you please help me in booking my flight ticket from IAD to DEN?

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are Aug 16 and Aug 18.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I need direct flight.

ASSISTANT: For booking, we need your good name. Please mention it.

USER: Myself Ashley Young.

ASSISTANT: May I know your class preferences?

USER: No, class preference but please check with connecting flight not with direct flight.

ASSISTANT: Sorry to say that, there are no flights available on he routes of your journey.

USER: Ok, thank you for your information.