Rewriting involves rereading. And then rereading it again. And rereading it still again. And so on.

Each time you read your manuscript you’ll find something that can be done differently. Better. Deleted. Added. Whatever …

So simply sit down at your computer and start reading what you wrote. Soon it’ll change and become better and better. And perhaps — and only perhaps — you’ll discover major changes that should be made. If that happens, then make those changes.