You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to book a flight ticket to DFW from OAK, can you please help me out?

ASSISTANT: Sure, I will help you. Can I have your planned travel dates please?

USER: Sure, my planned travelling dates are Aug 31 and Sept 02.

ASSISTANT: Can I have your name please for booking purpose?

USER: Sure, my name is Helen Harris.

ASSISTANT: Do you need a connecting flight or a direct flight?

USER: Yes, I prefer direct flight.

ASSISTANT: May I know your class preference?

USER: Any class is ok for me.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: Helen Harris, no flights has been found on your on your preferences.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.