You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Ruth Clark. Can you please assist me in booking a flight ticket from AUS to OAK?

ASSISTANT: May I know your desired travel dates please?

USER: My travel dates are Dec 22nd and Dec 24th.

ASSISTANT: Please wait a while, I will check and inform you.

USER: Sure, but the return time should be afternoon.

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

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.