When we read a book we like to guess how it is going to end. We want something logical, that makes sense based upon the action.
On the other hand, we also like to be surprised. We may enjoy the predictable, but we are startled when everything we thought was going to happen, does not.
So what do you do as a writer? If you stay with predictable, will your readers lose interest? Possibly. Why not try for an unexpected ending, something that readers don’t see coming. Even if your story doesn’t have a major twist in plot, there could be a shift that takes the readers in a direction that they couldn’t imagine.
Your task is to take something that you have written, a finished piece that maybe isn’t quite working the way you wanted, and change the ending. Instead of the butler doing it, maybe it was the car-share driver. Instead of getting the dream job, she gets hired to do something unrelated, but enjoyable.
The important thing is that your new ending must be satisfying. It must be justified by all that has happened in the story and therefor supported by the narrative.
Once you have rewritten the ending, reflect upon your work. Is it more satisfying? Does the surprise change the narrative so that predictability is altered? Hopefully you will discover something new in the process.
Have fun with this one.