found this after I posted - Code requires that the underside of the closet flange must be flush to the finished floor, which then leaves the top of the flange approximately 3/8" above the finished floor. In instances where they have installed tile or additional underlayment and the flange if left flush with or below the floor level the correct solution is to install a "Buildup flange"

Again what do you do if the flange is higher than code?

If the flange is higher you have two options.

1. Lower the flange to the prescribed height.

2. Build up the floor immediately under the bowl.

Cut it. I just today tackled this problem with a new shower drain that was about 3" higher than the pan (for the rubber cap to attach to until construction was done). After doing some research here, I found out there is such a thing as an internal PVC cutter. I picked one up at HD for $11. Tried it tonight and it worked perfectly. It's just a little circular blade screwed to the end of a steel rod that fits in any drill. I would try this before building up the floor.

Using the PVC ID cutter is fine if you have PVC or ABS drains, but if its cast iron or in some extremely rare instances, DWV grade copper its another problem entirely, especially if that flange is on a slab installation.

They make thin sheets of PVC material that can be set over the flange and the material cut to the contour of the bowl to make a buildup shim, On the other hand, if this is over a basement or crawl space it may be more desirable to cut the line then reset the flange.

That's true, I didn't consider that it might be cast iron. If's its in a basement, and the floor is easily replaced, it may be worthwhile to take up the flooring, open the slab and dig a little. Messy, labor intensive operation though. I guess the solution will depend on the location of the affected appliance and the tools/skill level of the homeowner. I think lazypups idea of using the sheeted PVC to make a shim in the shape of the bottom of the bowl is probably the simplest solution. You could probably easily fashion one yourself (plywood?) if you can't find the material locally.