Step 4 · Remove Flange-to-Floor Fasteners
Locate the screws that secure the flange to the subfloor. Using a drill with a driver bit or a screwdriver, attempt to remove these screws. If the screws are old and rusted, they may strip or break. If a screw head strips, you may need to use a screw extractor bit. If the screws are completely seized, a good option is to use an oscillating multi-tool or a reciprocating saw with a metal-cutting blade to carefully cut the screws flush with the floor, between the flange and the subfloor. Once all fasteners are removed, the flange should be loose from the floor but still attached to the drain pipe.