All writing is re-writing, and that's never more true than when it comes to narrative prose. A story, down to ever single plot beat and character turn, has to re-litigated and revised by its author ad nauseum until it begins to approach usable. And since the most important part of any story is often the ending, it's that particular section that often sees the most significant 11th-hour revising.
Being one of the most prolific and widely-recognized horror authors of all time, Stephen King's oeuvre has more than its fare share of "what could have been" in regards to how his stories closed out. Sometimes these changes are relatively minor and don't effect the overall narrative beyond a few minor details. Other times they have massive, wide-reaching consequences that stretch beyond just the initial novel and into spin-off and crossover works.
Whether it's a few small changes to the final chapters or massive overhauls of entire stories; here are some of the endings that very well could have been, but never were.