You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Jason Anderson here. I want to visit Washington so please book me a ticket from IAD to MSP.

ASSISTANT: May I know your desired travel dates please?

USER: Sure, my travelling dates are 07/07 and 07/09. Sure, I will wait for your reply.

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

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

ASSISTANT: Thank you for contacting us.