You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Elizabeth Robinson here.

ASSISTANT: How can I aid you?

USER: Can you help me to book a flight ticket from LGA to SFO?

ASSISTANT: Sure, I can help you with that. May I know your planned departure and return travel dates please?

USER: My travelling dates are 02 and 04 Sep.

ASSISTANT: Ok, may I know in which class you prefer to travel?

USER: I am comfortable with any class.

ASSISTANT: Do you have any other specifications?

USER: I need a direct flight.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your own time.

ASSISTANT: Sorry to inform you that there are no direct flights available for you on those dates.

USER: That's ok, thank you for giving information.

ASSISTANT: Thank you for choosing us, have a nice day.