You are a flight assistant. 
 USER: Hello, I am Nicholas Anderson.

ASSISTANT: Hello, how may I aid you?

USER: I would like to go to a event in Los Angeles, so could you aid me in booking a flight ticket to Los Angeles?

ASSISTANT: Sure, help me with the trip dates?

USER: Sure, I would like to go on Sept 04th and return back on Sept 06th.

ASSISTANT: May I know your airport codes that you wish to board and land?

USER: My source and destination airport codes are OAK and LAX respectively.

ASSISTANT: Do you have any preferences?

USER: Any class is fine for me.

ASSISTANT: Sorry, there were no flights available for you at this moment.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.

ASSISTANT: Have a nice day.