  Changing-look active galactic nuclei (CLAGNs) show the disappearance and
reappearance of broad emission lines in a few years, which challenges the
orientation-based AGN unification model. We reduce the X-ray data for five
well-studied CLAGNs that show a strong change in broad emission lines in the
past several decades. We find that the X-ray photon index, $\Gamma$, and the
Eddington-scaled X-ray luminosity, $L_{\rm 2-10 keV}/L_{\rm Edd}$, normally
follow negative and positive correlations when the Eddington ratio is lower and
higher than a critical value of $\sim 10^{-3}$. We find that the CLAGNs
observed with broad H$\beta$ emission lines stay in the positive part of the
$\Gamma-L_{\rm 2-10 keV}/L_{\rm Edd}$ correlation, while the broad H$\beta$
lines become weak or disappear in the anticorrelation part of the
$\Gamma-L_{\rm 2-10 keV}/L_{\rm Edd}$ correlation, which suggests that the
evolution of the broad lines should be correlated with the evolution of the
underlying accretion process. We further find that the CLAGNs are consistent
with the other different types of AGNs in the $L_{\rm bol}-L_{\rm bol}/L_{\rm
Edd}$ correlation. These results support that the CLAGNs are belong to a
special stage of AGNs with a bolometric Eddington ratio $\sim$1\%, where the
broad emission lines are easily affected by the strong variation in ionization
luminosity that is caused by the transition of accretion modes.
