Rewriting is reworking finished material: the content survives, the telling changes. The writer takes a source, breaks it into points, and puts each point in their own words. No new facts, examples or conclusions are added, because that part is not the rewriter’s job.
A word about names, since they cause half the confusion. English does not sell rewriting as a trade of its own. You will see it offered as content rewriting or article rewriting, or folded into editing. So this article talks about the work rather than the label: retelling material that exists, against writing material that does not.
The work comes in three depths. A light rewrite swaps words and reorders phrases, and it usually shows: the line of thought is still borrowed. A deep rewrite is a retelling from the points, with the source closed and a fresh outline. An SEO rewrite is the deep version aimed at search, with the terms people type in the headings and the opening.
The job covers reading the source, building a new structure, retelling it and checking the facts. It does not cover new material: nobody calls your expert, opens your figures or invents an argument the source never made. That is the boundary of the format, and the price grows out of it. The process itself has a separate guide — How to paraphrase a text: a step-by-step guide with examples.