You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Please book a flight ticket from SEA to IAH?

ASSISTANT: Sure, please share me your trip dates.

USER: My journey dates are Dec 16 and Dec 18.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I need a direct flight.

ASSISTANT: For booking, we need your good name. Please mention it.

USER: I am Carolyn Garcia.

ASSISTANT: May I know your class preferences?

USER: I am comfortable with any class.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for opting us.