You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am John Young.

ASSISTANT: Young, how can I aid you today?

USER: Help me with booking ticket from OAK to DCA, to visit the National Archives Museum.

ASSISTANT: Sure Young, I am here to help you. May I know your travel dates please?

USER: Ok, my trip dates are from 04/16 and 04/18.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Ok, take your time.

ASSISTANT: Sorry Young, there are no flights available on your requested dates.

USER: It's ok, thanks for your information.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.