You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: Can you aid me to book a flight ticket from DEN to ORD?

ASSISTANT: Sure, may I know the travelling dates?

USER: My trip dates are Nov 15 and Nov 17 respectively.

ASSISTANT: Do you have any connection limit?

USER: I prefer for connecting flight to travel.

ASSISTANT: Is there any other requirements?

USER: No preferences.

ASSISTANT: May I know your name?

USER: Brian Moore here.

ASSISTANT: Sorry, no flights found with your chosen dates.

USER: Thank you for the help.

ASSISTANT: Thank you for opting us.