You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I would like to travel from DEN to HOU, can you help me to book a flight ticket?

ASSISTANT: Sure, I am here to help you. Please let me know your travelling dates.

USER: My travel dates are Dec 06 and Dec 08.

ASSISTANT: Do you have any break in between journey?

USER: Yes, I prefer break in between my journey.

ASSISTANT: Is there any other specifications for you?

USER: I would like to return back in the evening time and an economy class flight ticket.

ASSISTANT: May I know your good name?

USER: I am Kathleen Young.

ASSISTANT: Sorry, no flights are available on your journey routes.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.