You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I have a plan to visit Denver. Please help me in booking flight ticket from SEA to DEN.

ASSISTANT: Your travelling dates please?

USER: My trip dates are Mar 22 to Mar 24.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight in economy class.

ASSISTANT: May I know your name please?

USER: I am Scott Thomas.

ASSISTANT: I am sorry no flight found on your route.

USER: Ok,no problem. Thank you for your quick service.

ASSISTANT: Thank you for choosing us.