You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Emily Evans here. I want to attend a Seminar in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: My travelling dates are 09/28 and 09/30.

ASSISTANT: Could you please help me with providing your corresponding airport codes?

USER: My airport codes are PHL and IAD. I want to departure on evening.

ASSISTANT: Do you have any other requirements?

USER: I want to travel in single connecting flight.

ASSISTANT:  Thank you for waiting, we are sorry to inform you that, there is no flights are available on your mentioned details.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you.