OK, not sure how this will pan out, but here goes.
The difference between revising and rewriting is the same as the difference between dreaming and doing. In other words, revising is where you think about how your first draft fits with what you saw/felt/heard in your head. You make notes to yourself on where your draft leaves you flat, or your characters aren’t sounding right, or where you see a redirection is needed. It involves big plans and aiming high.
Rewriting is putting your money where your mouth is, so to speak. It’s when you have to sit down and wrestle with your characters and plot until hopefully you bring things together better than they were before. It’s getting down and dirty in the detail, up to your elbows in scenes and sentences. You come up for air, blinking and gasping, and then plunge back in again.
What I don’t know yet, is how much of the revising makes it into the rewriting. Stay tuned!