You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How can I be your helping hand?

USER: I am Mark Thompson. I need a direct flight to Washington, As I am a journalist I want to collect some data from library of congress.

ASSISTANT: Ok.

USER: Can you please help me in booking within the price of 500.

ASSISTANT: Sure. Could you please provide your origin and destination airport codes?

USER: Sure, my origin point is Philadelphia, PHL and destination point is Washington, DCA.

ASSISTANT: Do you have connection limit? Let me know your travelling dates.

USER: I wish to start on 12/18 and return from Washington on 12/20.

ASSISTANT: Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: I am happy to say that there is a flight available with Southwest airline, fight number 1021.

USER: If it is a direct flight, then please proceed with booking.

ASSISTANT: No, it is not a direct flight.

USER: Please terminate the booking.

ASSISTANT: Your booking has been terminated.

USER: Thank you for your help.

ASSISTANT: Thank you for approaching us.