You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I want to book a ticket from LAS to IAD. Could you book a ticket?

ASSISTANT: Sure, may I know your planned travel dates?

USER: Travel dates are from Sept, 16 to Sept, 18.

ASSISTANT: May I know your connection limit?

USER: I prefer connecting flight.

ASSISTANT: Is there any class preference for you?

USER: I would like to prefer business class.

ASSISTANT: Your good name please.

USER: Mu name is Christopher Lewis.

ASSISTANT: Do you have any other specifications?

USER: I would like to depart in the afternoon.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Thank you.

ASSISTANT: Thank you for reaching us.