You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Can you please help me in booking a flight ticket from DCA to DEN?

ASSISTANT: May I know your trip dates?

USER: Sure, my travel dates are from July 23 to July 25.

ASSISTANT: Do you prefer any connections?

USER: I would prefer connecting flight for my trip.

ASSISTANT: Are you looking for any specifications?

USER: No.

ASSISTANT: May I know your name?

USER: Paul Nelson here.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.