You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Dennis Brown, I am planning to visit World Mobile Congress at Austin, can you book a flight 04/09?

ASSISTANT: Sure, could you please mention your price limit?

USER: My budget is 500 for flight ticket.

ASSISTANT: Can I have your return date?

USER: I will return on 04/11.

ASSISTANT: Do you need any stopover in between journey?

USER: I need a halt in between the journey.

ASSISTANT: Kindly mention your source and destination?

USER: My source point is CA-OAK and destination is TX-AUS.

ASSISTANT: Ok, please wait couple of minutes.

USER: Sure.

ASSISTANT: Thanks for your time, sorry, no flights found on that day.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for availing us.