You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I have planned to visit National Air and Space Museum in Washington, can you please check the flight available on the dates June 14 and June 16?

ASSISTANT: Sure, help me with the airport codes?

USER: Thank you. The preferred airport codes are HOU and DCA.

ASSISTANT: Do you have any airline preferences?

USER: I am looking to travel in a normal-cost airlines.

ASSISTANT: May I know your name please?

USER: My name is Paul Scott.

ASSISTANT: We have an economy class, connecting flight operated by United Airlines with a fare of 100. Is it ok for you?

USER: I prefer a business class flight. Can you please check once again?

ASSISTANT: Sorry, economy class is available right now.

USER: It's ok, not a problem with that. Thank you for your time in searching the flights.

ASSISTANT: Ok, thank you for reaching us. Have a nice day.