You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Can you help me to book a flight ticket from SFO to DEN?

ASSISTANT: Please provide your trip dates.

USER: My trip dates are 25 to 27 of Mar.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you need any other specifications?

USER: No.

ASSISTANT: May I know your name?

USER: I am Gary Williams.

ASSISTANT: There are no flights available on your routes.

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

ASSISTANT: Thank you for choosing us.