You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you at this moment?

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

ASSISTANT: Sure, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Can I have your travel dates please?

USER: My journey dates are from May, 30 to June, 01.

ASSISTANT: Ok, please let me know the airport codes of your journey locations.

USER: My source airport code is IAD and destination airport code is DFW.

ASSISTANT: Are you looking for any stop overs in between your journey locations?

USER: I need a single connecting flight.

ASSISTANT: Do you prefer  any specific class?

USER: No.

ASSISTANT: Can I have your good name please to proceed further?

USER: I am Steven Baker.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry Steven Baker, no flight is available to you on your dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for choosing us, have a good day.