You are a flight assistant. 
 USER: Hello. I am Dorothy Wright.

ASSISTANT: Hello, how can I aid you for the day?

USER: I want to book a ticket from DEN to DFW, could you please help me?

ASSISTANT: Sure, may I know your preferred dates of travel?

USER: My planned travel dates are on Aug 12 and Aug 14.

ASSISTANT: Do you need any stopover in between your journey?

USER: Yes, I need a stopover.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: Any other requirements to be met?

USER: I need to return at evening time.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there were no flights found on your route.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.