You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Can you please book a flight ticket in business class?

ASSISTANT: Sure, may I know your journey points?

USER: My airport codes are, ORD to IAD.

ASSISTANT: Can I know your travel dates?

USER: My journey start on Mar 9th, and arrival on Mar 11th.

ASSISTANT: Do you have any other requirements?

USER: I prefer a flight with single connection.

ASSISTANT: May I know your name?

USER: My name is Helen Smith.

ASSISTANT: Sorry, there were no flights found with your requirements.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.