You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I need your assistance in booking a flight ticket, can you?

ASSISTANT: Sure, can I know the travel dates please?

USER: April 22 and 24 are my planned travelling dates.

ASSISTANT: Could you please provide the airport codes?

USER: OAK and ATL are my depart and return airport codes.

ASSISTANT: May I know the connection limit please?

USER: I need to attend an emergency operation. So I need a direct flight.

ASSISTANT: Do you have any requirements?

USER: I prefer to fly in a business class airlines.

ASSISTANT: May I know your name please?

USER: Sure, my name is Michael Perez.

ASSISTANT: Ok, wait a moment please.

USER: Ok, I will wait until you respond.

ASSISTANT: Sorry, there are no flights available as per your request.

USER: I haven't expected this. Thank you.

ASSISTANT: Thank you for approaching us.