Illustration of one possible geometrical change in AGN accretion structures due to the major CLAGN transition occurring after 2013. Length scales as illustrated here are approximate only. (a) Bright state configuration: warm corona present in the inner accretion structure along with the hot-accretion flow or corona or less dominant ADAF. (b) Faint state configuration after ∼2021: warm corona disappears (Sect. 4.2) and the inner accretion flow becomes dominated by a hot ADAF (Sect. 4.3), emitting X-rays and UV seed. The thin disk also decreases its energy contribution and physical size. Finally, the broad line region (BLR) + torus system extends from sub-parsec scale to 10 s of parsecs, which results in significant smoothing of the Fe Kα line response (Sect. 4.6.1 and Fig. 9).