Abstract Changing-look active galactic nuclei (CLAGNs) show the disappearance and reappearance of broad emission lines in a few years, which challenges orientation-based AGN unification model. We reduce X-ray data for five well-studied CLAGNs that strong change past several decades. find photon index, ?, Eddington-scaled luminosity, L 2–10 keV / Edd , normally follow negative positive correlati...
