We cannot change the past, but only the way we choose to do things in the present moment. And we can indeed take new and different action than we did yesterday.
We can be haunted by our past from what we chose to do and what not to do (It would seem for me, it’s more about what I didn’t do). And I’ve found the best way to dissipate the ghosts of my past is to attack the present moment with passion and fervor.
I’m not a fan of horror movies and I certainly don’t need any more ghosts from my past paying me visits. And so I use engagement and actions in the areas of my life where I’m afraid or unsure of how to move forward as my (Harry Potter) Patronus Charm.
This seems to keep my “demons” at bay.