You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I  help you?

USER: Shirley Harris here. I want to attend a Seminar in Chicago. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, may I know your airport codes please?

USER: My airport codes are SFO and ORD.

ASSISTANT: Your travelling dates please?

USER: My travelling dates are 07/20 and 07/22.

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

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing us.