Hi there. Here is a picture of the flange from a our prior coach (2011 Flying Cloud), which is probably similar to your flange. Like you, I wanted to rotate the toilet (in our case, we wanted to straighten it as it pointed too far toward the door). I removed the 8 pictured Phillips head screws, and was then unable to make the flange rotate at all, even with substantial rotational force, and gave up. I hope you have better luck (and more ingenuity) then I did.
Best,
Joe