I haven't quite gone that far, but the novels I've written definitely evolved over time. I usually start by working on a barebones structure -- so I know where I'm headed. But there's a lot that can happen between point A and point B. And sometimes I do realize an interesting idea late in the process, or realize that there's a certain scene that needs to be changed or deleted because it slows down the plot.
It does help to really outline you work ahead of time -- you can often figure out where the holes are before you even sit down to write. Then you don't have to go back and delete so much later.