You don’t. Scrape it off or cover it up!
Terri: I feel your pain. I HAD popcorn ceilings in my house... but paid to have them scraped off. THE best decision ever! However, I used to take a soft bristled broom and "sweep" the ceiling... it got off webs and some dust. Then vacuum up the mess.
Reverse tape around a paint roller. May need to change when it's full and not sticky.
I vacuum mine. Hate it, but can't afford to remove at the current time.
Remove the outdated ceiling and remove the imperfections , smooth and paint.