You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, please provide your journey dates.

USER: My trip dates are 13 to 15 of Oct.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you need any other specifications?

USER: Sorry, I need a direct flight.

ASSISTANT: May I know your name?

USER: I am Gregory Garcia.

ASSISTANT: There are no flights available on your routes.

USER: That's ok, thank you for giving information.

ASSISTANT: Thank you for choosing us.