You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

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

ASSISTANT: Sure. May I know your name.

USER: My name is Patrick Turner.

ASSISTANT: When would you like to travel?

USER: My travelling dates are Mar 22 and Mar 24.

ASSISTANT: Could you please let me know your  airport codes?

USER: My airport codes are IAD and SFO.

ASSISTANT: Do you have any other specifications?

USER: I want to travel in business class. I need single connecting flight.

ASSISTANT: Ok. We are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you.