You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Can you help me to reserve a flight ticket from DEN to HOU?

ASSISTANT: Please provide your travelling dates.

USER: My trip dates are 17 to 19 of Mar.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Do need any other specifications?

USER: No.

ASSISTANT: May I know your name?

USER: I am Nicholas Robinson.

ASSISTANT: There are no flights available on your routes.

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

ASSISTANT: Thank you for opting us.