Often, Joseph, it can be merely be softened with water. Via, maybe a pump up sprayer and scraped off using a drywall tool. But if it was applied with paint in the mix or has been painted over, not sure.

my recommendation is not as sloppy messy as glkirk builders... but just as messy and dusty... use a scraper with a long handle to scrape off the primary popcorn then repair and sand down to smooth ceiling (if that is what you desire).