You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Donna Harris here. I want to book a flight ticket from DFW to LAS. Can you help me in that?

ASSISTANT: Sure, we are here to help you with that flight ticket booking. May I know your journey dates, please?

USER: Sure, my trip dates are May 14 to May 16.

ASSISTANT: Do you need a halt in between your journey?

USER: I need a connecting flight and make sure that my return time should be in evening.

ASSISTANT: Sorry, there are no flights available as per your travel dates. Thank you for reaching us, have a nice day.