Take Life of an American Fireman for example. It was the progenitor of what is probably the basis of modern film editing: cross-cutting a seamless narrative. But Porter didn't do this in the original cut. However, without any dialog, audiences were confused about what was going on, so he re-cut it. This is a more obvious example. I could list many others, but it best makes the point, I think.
This is a bit tangential, but I haven't read any research which suggests that Porter himself re-edited the film to cross-cut the sequences. Rather, it was re-cut in 1910 (or perhaps even later), at least a year after Porter left Edison's company (and, I presume, had anything to do with that earlier silent).