You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Jacob Miller here. Please help me out in booking the ticket from SEA to DCA.

ASSISTANT: May I know your desired travel dates please?

USER: Sure, 08/09 and 08/11 are trip dates.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Its ok, no problem. Thank you for your information.