You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I would like to meet my friend at Denver, can you please help me to book my flight ticket from AUS to DEN?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, I will depart in the evening on Nov 4th and return back on Nov 6th.

ASSISTANT: May I know your name please?

USER: My name is Christopher Garcia.

ASSISTANT: There is a flight with connection limit 1 and fare 100, shall I proceed for booking?

USER: I prefer for an economy class.

ASSISTANT: There is a flight with economy flight.

USER: I need normal-cost airlines.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Sad to hear that. Anyway, thank you for checking.

ASSISTANT: Thank you for opting us.