Best way to rewrite ebooks?

Hello BHW'ers!

Okay, So I got some good ebook right now, and I would like to know how to effectively rewrite ebooks. Do I use a rewriter, or do I copy/paste/edit my way through the whole ebook?

Thanks in advance:
Fenchel

if its PLR ebook you can do whatever you want
but if you dont have rights you only can revrite it fully

just outsource that work at freelancer