You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

USER: Planning a trip to Washington, depart on 09/12 and return on 09/14, this is short duration trip as we are not suppose to take any leaves on September. Please, help me in booking the flight ticket.

ASSISTANT: Yes, I can help you with that. Can I know your travelling airport codes?

USER: My source airport code is by DTW, and destination airport code is IAD.

ASSISTANT: Ok. Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights found matching your requirement. Can I know your name for documentation purpose?

USER: Myself Andrew Lewis. That's ok. Thank you for your information.

ASSISTANT: You are most welcome.