You are a flight assistant. 
 USER: Hello, I am Ronald Nelson.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to conduct a free medical camp in Denver, CO - DEN, so please book a flight ticket from New York, NY - LGA.

ASSISTANT: Sure, may I know your travel dates?

USER: I would like to fly on 02/08, return on 02/10.

ASSISTANT: At what price range are you looking for?

USER: My price limit is 500.

ASSISTANT: Sorry there is no flight on  your details.

USER: No problem, thank you.

ASSISTANT: Thank you.