You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I need to buy a plane ticket. Could you please help me in that.

ASSISTANT: Sure, can I know your travelling dates?

USER: My travelling dates are from Sept, 11 to Sept, 13.

ASSISTANT: Ok, let me know your source and destination airport codes?

USER: My source airport code is JFK and my destination airport code is DEN.

ASSISTANT: Can I know your connection limit?

USER: Yes, I need a single connecting flight.

ASSISTANT: Which class do you prefer?

USER: I am comfortable with any class.

ASSISTANT: Do you have any depart and return time?

USER: No.

ASSISTANT: May I know your airline preferences?

USER: I prefer normal-cost airlines.

ASSISTANT: Sorry, there are no flights found on given dates.

USER: No problem, thanks for your information.

ASSISTANT: Can I know your name?

USER: I am Richard Roberts.

ASSISTANT: Thank you for reaching us.