You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Please help me to book a flight ticket from LAS to DEN.

ASSISTANT: Sure, I am here to help you in booking. Can you please share your travel dates?

USER: My travelling dates are 04 to 06 of Sep.

ASSISTANT: Ok, please share your name.

USER: I am Barbara Campbell.

ASSISTANT: Let me know your connection limit.

USER: I need a connecting flight.

ASSISTANT: Do you have any specification?

USER: I prefer to return in the afternoon.

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

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

ASSISTANT: Thank you for reaching us, have a nice day.