You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Ronald Green.

ASSISTANT: Green, how may I aid you?

USER: I have a business meeting in Washington, can you help me for booking a flight ticket from LAS to DCA?

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

USER: My travelling dates are 12/02 and 12/04.

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

USER: That's ok, thank you for your information.

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

USER: Welcome.