You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Can you help me to book a flight ticket from DCA to ORD?

ASSISTANT: Sure, I can help you with that. May I know your planned departure and return travel dates please?

USER: My trip dates are 29 to 31 of Dec.

ASSISTANT: Do you need break in between your journey?

USER: I need a connecting flight.

ASSISTANT: Please let me know if you have any other specifications.

USER: I prefer to travel in business class.

ASSISTANT: May I know your good name please?

USER: I am Michael Adams.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: It's ok not a problem, thank you.

ASSISTANT: Thank you for choosing us, have a nice day.