You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I want to visit San Francisco to attend my conference meeting. Please help me in booking my ticket from Las Vegas.

ASSISTANT: Sure, I will assist you with that. Can you please mention your preferable travel dates?

USER: Thank you and my travelling dates are from 09/17 to 09/19.

ASSISTANT: Could you please mention your preferable airport code names for further process?

USER: My airport codes are from LAS to SFO.

ASSISTANT: May I know your name for further process?

USER: Myself Justin Smith.

ASSISTANT: Do you have any preferences regarding timings of your journey?

USER: No.

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

USER: I need a single connecting flight.

ASSISTANT: Do you have any another specifications?

USER: No.

ASSISTANT: Ok, please hold on a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for reaching us.