You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Nancy Martinez. I want to book a flight ticket from AUS to SEA. Could you help me in booking?

ASSISTANT: Sure, I am here to help you. May I know your travel dates?

USER: My travelling dates are from Dec 18-20.

ASSISTANT: Ok, do you have any class preference?

USER: No.

ASSISTANT: Ok, may I know your specifications?

USER: My return time should be in the afternoon and I need connecting flight.

ASSISTANT: Sorry, there is no flight available as per your requirements.

USER: That's ok, no problem. Thank you.

ASSISTANT: You are welcome and have a nice day.