You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Please provide your trip dates.

USER: My trip dates are Jul 4 and Jul 6 respectively.

ASSISTANT: Do you need any connection limit?

USER: I prefer for connecting flight.

ASSISTANT: Do you have any other specifications?

USER: I prefer for business class flight to travel.

ASSISTANT: May I know your name?

USER: Ryan Miller here.

ASSISTANT: There are no flights available on your routes.

USER: Thank you.

ASSISTANT: Thank you for opting us.