Rewriting history is a crime. Rewriting somebody’s personal history is a crime against the individual ‑ even on request. Rewriting is done by people who don’t understand what therapy is, probably because they don’t understand what life is about, what people are.
There are two types of rescripting, that done by the client himself, without awareness of the therapist, and that induced by the therapist as a conscious intervention. Why clients rescript, is simple: they resist facing the truth because of shame, guilt, humiliation, or sheer terror. The real memory is overwhelming, or ‑ as often ‑ resisted because it threatens a cherished self-image.