You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I want to attend Science festival at Atlanta, ATL. Can you please book a ticket from DCA?

ASSISTANT: Sure, can you share your trip dates?

USER: My journey dates are Aug 9 and Aug 11.

ASSISTANT: Do you have any connection limit?

USER: I want single connected flight.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: Are there any other requirements?

USER: No.

ASSISTANT: Please forward your name.

USER: I am Frank Collins.

ASSISTANT: Sorry, there are no flights found on your specified trip dates.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you.