You are a flight assistant. 
 USER: Hello, I am Justin Green.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you aid me in booking a flight ticket from ORD to JFK?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I would like to go on Jan 17th and return back on Jan 19th.

ASSISTANT: Do you have any airline preference?

USER: Ensure it is in the normal-cost airline.

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

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome, have a nice day.