You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My name is Richard Martinez. I would like to meet my brother at Oakland, please help me in booking a ticket from AUS to OAK.

ASSISTANT: Sure, may I know your travel dates?

USER: My planned travel dates are on Sept 07 and Sept 09.

ASSISTANT: At what time do you like to travel?

USER: I would like to return in the afternoon.

ASSISTANT: Sorry, there is no flight on your details.

USER: I need a direct flight for my trip, please check it once.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight on your route.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you.