You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Dennis Davis. I am looking for a flight from SFO to LAX, can you please help me booking?

ASSISTANT: Sure, when are you going to travel?

USER: My travelling dates are Feb 15 and Feb 17.

ASSISTANT: Do you have any specific time to depart and return?

USER: I want to depart and return in evening time.

ASSISTANT: Can I know your class preference?

USER: I am fine with any class.

ASSISTANT: Sorry to say, currently there are no flights available.

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

ASSISTANT: Thank you for approaching us.