You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: I would like to prefer a economy class flight for my holiday trip to Oakland. So can you book a flight ticket for me?

ASSISTANT: Sure, I am happy to help you with the ticket booking. Could you please tell me the airport codes of your desired locations.

USER: The airport codes are from LGA to OAK.

ASSISTANT: Ok, on which dates you are looking to book a flight ticket?

USER: My trip dates are from July 05 to July 07. Sorry Instead of economy class look for a business class.

ASSISTANT: Sure, I will check for that. Is there any other specifications?

USER: I need a single connecting flight.

ASSISTANT: I regret to inform you that, there is no flight available in the business class in this route.

USER: Not a problem. Thank you.

ASSISTANT: You are most welcome. Have a nice day.