You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, can I know your good name please?

USER: Sure, my name is Justin Collins.

ASSISTANT:  When you are willing to travel?

USER: Sure, my willing to travel dates are from Jan, 16 to Jan, 18.

ASSISTANT: Do you need direct flight or connecting flight?

USER: Yes, I need a connecting flight.

ASSISTANT:  Is there any other specifications?

USER: Yes, I want to depart at evening time.

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

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for opting us.