chasbro:
Personally, I often download stories & rewrite them to suit my personal tastes. Changing words, implements, number of strokes, sometimes a lot of stuff.
Strictly speaking you ought to have the author's permission to do that, but if it is only for personal use no sane author would care, and it might well be covered by fair use (in the US at least) anyway. If you were to repost the modified versions, then you
really ought to get permission, in my view.