You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to attend a Marriage in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: May I know your desired travel dates please?

USER: My travelling dates are June 06 and June 08.

ASSISTANT: Can I know your preferred airport codes please?

USER: My airport codes are IAH and IAD.

ASSISTANT: May I know your name please?

USER: My name is Pamela King.

ASSISTANT: Do you have any specifications?

USER: I want to travel in business class flight. I need a nonstop flight.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for opting us.