You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Could you please help me in making a plane reservation from IAD to reach Atlanta?

ASSISTANT: Sure, can you share your trip dates?

USER: My trip dates are on Dec 31st to Jan 2nd.

ASSISTANT: May I know your landing airport code?

USER: My landing airport code is ATL.

ASSISTANT: Do you have any preferences?

USER: I need an economy class.

ASSISTANT: May I know your name?

USER: Sure, my name is Patrick Garcia.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Not a problem, thank you.

ASSISTANT: Thank you for opting us.