Remove the Toilet
Disconnect the toilet supply tube from the toilet stop.
Shift the toilet back and forth while lifting it off the flange. If you're working alone, remove the tank by unbolting it from the bowl before you attempt lifting the toilet from the flange.
To prevent sewer gases from entering your bathroom, stuff a rag into the drain opening.
Scrape all the old wax from the flange, and check for cracks. If the flange is cracked, replace it. Be sure to wear gloves when scraping off the old wax.