You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Steven White.

ASSISTANT: How can I aid you at this moment?

USER: Can you help me in booking from LAS to DCA?

ASSISTANT: Sure, I am here to help you. Could you please share your journey dates?

USER: My travelling dates are from Feb 26 to Feb 28.

ASSISTANT: Do you have any connection limit for this journey?

USER: I need a connecting flight.

ASSISTANT: May I know your specific depart and arrival timings for this trip?

USER: My return time is evening.

ASSISTANT: Do you have any other specifications for this trip?

USER: No.

ASSISTANT: Steven White, there are no flight services are available on this route with your preferences.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for contacting us.