You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Please book me a flight ticket from DCA to LAS to meet my family members.

ASSISTANT: Sure, May I know the travelling dates?

USER: I have planned to travel on Sept 06th and return on Sept 08th.

ASSISTANT: Do you have any connection limit?

USER: I like connecting flight with business class.

ASSISTANT: Is there any other requirements?

USER: I like business class.

ASSISTANT: May I know your name?

USER: Joshua Green.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.