You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello! tell me how can I help you?

USER: I am Melissa Nelson, I want to book a flight ticket.

ASSISTANT: OK, can you please tell me your journey dates and codes of your journey?

USER: The source airport is DC- IAD and the destination airport is PA-PHL. The journey dates are 06/12 and 06/14. Please check for the flight with price 200 and with zero connection.

ASSISTANT: There are no flights found on your desires sorry for the inconvience. Thank you for contacting us.