You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to book a flight ticket to AUS from IAH, can you please help me out?

ASSISTANT: Sure, help me with the trip dates?

USER: Sure, my  trip dates are Dec 08 and Dec 10.

ASSISTANT: Do you have any preferences?

USER: Yes, I prefer business class.

ASSISTANT: May I know your name please?

USER: Sure, my name is Nancy Clark.

ASSISTANT: Sorry, we did not find any flights running in your preferred dates.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for opting us.