You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Please book a ticket from SFO to OAK.

ASSISTANT: May I know your desired travel dates please?

USER: Travel dates are Sept 2 and Sept 4.

ASSISTANT: May I know your name please?

USER: I am Larry King.

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

USER: Thank you.

ASSISTANT: Thank you for opting us.