You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am searching for the business class flight from San Francisco, can you please help me to book a flight ticket?

ASSISTANT: Sure, I am here to help you. Can you please share your travel dates?

USER: Thank you for accepting my request. My preferred journey dates are Feb 18 and Feb 20.

ASSISTANT: May I know your airport codes?

USER: The source and destination airport code s are SFO and LAS.

ASSISTANT: May I know your connection limit?

USER: I am looking for a direct flight for my journey.

ASSISTANT: Do you have any other requirements?

USER: I would like to return back in evening time.

ASSISTANT: Ok, please let me know your name.

USER: Sure, Rachel Wilson here.

ASSISTANT: Please be on hold.

USER: Sure, please provide me a best flight.

ASSISTANT: Sorry, there are no flights in this route as per your travelling details.

USER: It's ok, not a problem with that. Anyways thank you for searching the flights for me.

ASSISTANT: Thank you for choosing us.