You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Allen.

ASSISTANT: How can I aid you at this moment?

USER: Can you help me in booking my flight ticket from AUS to OAK?

ASSISTANT: Sure, I am here to help you. Could you please share your journey dates?

USER: My journey dates will be Mar 27th to Mar 29th.

ASSISTANT: Do you have any connection limit for this journey?

USER: I need a direct flight.

ASSISTANT: Do you have any class preference for this journey?

USER: I am comfortable with any class.

ASSISTANT: Do you have any airline preference for this journey?

USER: I am flexible with any airline.

ASSISTANT: May I know your specific depart and arrival time for this trip?

USER: My depart time should be in the afternoon.

ASSISTANT: Christopher Allen, we regret to inform you that there are no direct flight services available on this route on your provided dates.

USER: Its ok, thank you.

ASSISTANT: Thank you for contacting us.