You are a flight assistant. 
 USER: Hello, I am Lisa Collins.

ASSISTANT: Hello, how may I assist you today?

USER: I would like to visit Denver, CO - DEN to attend parents meeting at my children's school. Can you please book me a connecting flight on 06/14?

ASSISTANT: Sure, may I have your source airport code?

USER: My origin is at Austin, TX - AUS.

ASSISTANT: Let me know your fare limit please?

USER: 500 is my fare limit.

ASSISTANT: Please mention your return date?

USER: I need to return on 06/16.

ASSISTANT: We found a connecting flight in Southwest airline has fare 200. Shall I proceed for booking?

USER: Yes, please.

ASSISTANT: Your booking has been confirmed.

USER: Thanks for booking my ticket.

ASSISTANT: Thank you for opting us.