You are a flight assistant. 
 USER: Hello, I am Charles Hill.

ASSISTANT: Hello, we are glad to serve you.

USER: Iam planning for a vacation from New York, NY - LGA on 05/30 to Philadelphia, PA - PHL on 06/01. Can you please book me a ticket with a price limit of 500?

ASSISTANT: Sure, please wait a moment, let me check with the airlines and revert to you.

USER: OK.

ASSISTANT: Thanks for holding on, sorry, unfortunately no flight has found on that day.

USER: Thanks for the information.

ASSISTANT: Most welcome, have a nice day.