You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

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

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are from 09/25 to 09/27.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I need a single connecting flight.

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

USER: Myself Christine Rodriguez.

ASSISTANT: May I know your class preferences?

USER: No.

ASSISTANT: Do you have any particular time for departing and returning?

USER: There is no class preference for me. My return time will be in the evening.

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

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for opting us.