You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: This is Steven Campbell.

ASSISTANT: How may I assist you now?

USER: We are planning to watch a movie in IAH, would you please book a flight ticket from SFO?

ASSISTANT: May I know your journey dates?

USER: My journey dates are Mar 4th and Mar 6th.

ASSISTANT: Do you have any requirements?

USER: The depart time should be afternoon. I will prefer to travel in business class.

ASSISTANT: Sorry to say, there are no flights available for your journey.

USER: Ok, not an issue. Thank you.

ASSISTANT: Have a nice day.