You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I need to book a flight ticket from OAK to ATL, can you help me in booking a flight ticket?

ASSISTANT: Sure, Please share your journey dates?

USER: Sure, my journey dates are Mar 11 and Mar 13.

ASSISTANT: Do you have any specifications?

USER: I prefer a direct flight.

ASSISTANT: Is there any class preferences?

USER: No.

ASSISTANT: May I know your good name?

USER: Sure, Karen Thomas here.

ASSISTANT: Sorry, no flights found on your given details.

USER: Ok, no worries at all. Thank you for your information.

ASSISTANT: Thank you for choosing us.