You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,. How can I assist you?

USER: I want to travel from Seattle, WA - SEA to San Francisco, CA - SFO.

ASSISTANT: Sure, could you please provide your journey dates?

USER: The price limit be 200, and the travelling dates are 02/15 and 02/17.

ASSISTANT: May I know your good name?

USER: I am Jack Walker.

ASSISTANT: OK, will you please wait a moment?

USER: OK.

ASSISTANT: We are sorry to notify you that there is no flights available based on your details.

USER: OK, thanks for your information.

ASSISTANT: You are welcome.