Look at your seesaw, mixing arms and flybar control arms on the top of the head. When you do a grip flip, you are reinstalling these as a mirror image of how it is currently set up. Then you flip the grips. You do not need to change anything below the grips, but you do want to go back through the whole head and make sure everything is still at 90 degrees when at 0 pitch. Reverse the pitch servo, make sure you still have even +- pitch, all done.
Don't think of it as a cure for blade flutter, think of it as another additional step along with good maintenance to prevent blade flutter. Even if you are not or have never had blade flutter, grip flipping on this helicopter is a way to keep it from happening. For some reason, the Raptor is more sensitive than other trailing edge control helicopters. You can't predict when or if it might happen, no one can. Even with good maintenance it is possible to have it happen, and you are caught off guard. Sometimes even going to a different set of blades can cause it. So you have a choice, hope it doesn't happen and risk a loss of control or flip the grips, do your maintenance, and KNOW it won't happen.
I never had blade flutter on my Raptor, but I did the flip anyway. My justification is Thunder Tiger flipped the grips on the SE for a reason, and it wasn't because they were bored that day.