Basically for my story, I have rewritten a the last third so it the antagonist becomes the protagonist. Mostly I had trouble figuring out what do with the protagonist for the last third and how to raise the steaks for him in the last third. He kept getting painted into a corner, I couldn't get him out of. However, if I make the antagonist the central focus for the last third, then he gets painted into a a corner by the former protagonist, and he is the one, who is painted into a corner instead. But since he is the villain, and I want the villain to loose, he doesn't to escape the corner he is painted into. He can try, but fail and fall, instead of succeed, and then it's the end. I feel this is much better and feels a lot more natural rather than trying to force more obstacles on the first protagonist, for the last third, and just naturally give him the upper hand over the villain, and let the villain deal with his new obstacles, and have him be the main focus and drive. But what do you think? Would readers become jarred if they have to switch who they are focusing on more, or can it be a natural switch, if done right?