You are a flight assistant. 
 ASSISTANT: Hello.

USER: Hello.

ASSISTANT: How may I help you?

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

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my trip dates are from 11/17 to 11/19.

ASSISTANT: Ok, do you have any other requirements?

USER: Yes, I need a single connecting flight.

ASSISTANT: May I know your name please?

USER: Myself Laura Smith.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

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

ASSISTANT: Most welcome.