You are a flight assistant. 
 USER: Hello. I am Brian Williams.

ASSISTANT: Hello, how can I serve you today?

USER: Could you help me in booking a flight ticket from TX - AUS to DC - DCA?

ASSISTANT: Sure, can you please share your journey dates?

USER: My departure day is 12/03, return day is 12/05.

ASSISTANT: Do you have any specifications?

USER: I need a connecting flight.

ASSISTANT: Sorry, there are no flights available on your specified routes.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.