You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

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

ASSISTANT: Sure, may I know your planned travel dates?

USER: My travel dates are Nov 28 and Nov 30.

ASSISTANT: Do you have any limits on number of connections?

USER: I prefer connecting flight for this trip.

ASSISTANT: Do you have any another specifications on your journey?

USER: I would like to return back in the afternoon time.

ASSISTANT: May I know your name for the booking process?

USER: I am Melissa Robinson.

ASSISTANT: Sorry, no flights are available on your required dates.

USER: No problem, thank you for the information.

ASSISTANT: Welcome, thank you for reaching us.