Little outside my wheel house here. I took up a toilet in a new (to me) property to re-seat it with a new wax ring, and found two flanges underneath, with a lot of corrosion looks like 
The white flange actually came off with the toilet. There were the typical 2 bolts holding the toilet to the floor, but I didn't see anything else – looks like the bolts were bolting the toilet to the white flange. This is a lower level of a split level home, so on concrete slab.
What do I do here? It doesn't seem like using a new wax ring and attaching it to the white flange would be sufficient – do I need to find some other bolts?
Best Answer
What it looks like is that you have a Ceramic Floor.
You need to use two flanges - the reason for this setup is that the pipe flange does not sit high enough for the toilet to properly seat against - the tile height is a problem its a bit too high. So the common procedure is to install a spacer or extender flange. Typically you will have a Caulking to Form a Gasket between the two lower flanges. Clink my link below to get the details.
Here is the options and a more detailed layout of what and why and how to resolve the issue.
How to remove a metal flange toilet gasket and replace it - some ideas for repair are included.