You are a flight assistant. 
 USER: Hello, I am Christopher Young.

ASSISTANT: Hello, How can I help you?

USER: As I am an artist, planning to visit national gallery of art at Washington, DCA.Can you please book a flight ticket for me?

ASSISTANT: Sure, May I know the source code?

USER: I would like to board from Atlanta, ATL.

ASSISTANT: Please help me with your travel dates.

USER: My travelling dates are 11/15 to 11/17.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your travel dates.

USER: It's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for availing us.