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Mrk 1018 is a "changing-look" AGN whose optical spectrum transitioned from aType 1.9 to Type 1 between 1979 and 1984 and back to a Type 1.9 in 2015. Thislatest transition was accompanied by a decrease in X-ray flux. We analyze theChandra spectra from 2010 and 2016 and NuSTAR spectra from 2016, carefullytreating pile-up in the Chandra spectrum from 2010 and self-consistentlymodeling absorption, reflection, and Fe K$\alpha$ line emission in the X-rayspectra from 2016. We demonstrate that while the 2-10 keV X-ray flux decreasedby an order of magnitude (1.46$^{+0.10}_{-0.13} \times 10^{-11}$ erg s$^{-1}$cm$^{-2}$ to 1.31$^{+0.09}_{-0.04} \times 10^{-12}$ erg s$^{-1}$ cm$^{-2}$),the Fe K$\alpha$ equivalent width (EW) increased from 0.18$^{+0.17}_{-0.12}$ to0.61$^{+0.27}_{-0.25}$ keV, due to a depressed AGN continuum. We jointly fitthe Chandra and NuSTAR spectra from 2016 using the physically-motivated MYTorusmodel, finding that the torus orientation is consistent with a face-ongeometry, and lines of sight intersecting the torus are ruled out. While wemeasure no line-of-sight absorption, we measure a column density of $N_{\rm H}$= 5.38$^{+14}_{-4.0} \times 10^{22}$ cm$^{-2}$ for gas out of the line-of-sightwhich reprocesses the X-ray emission. We find a high relative normalizationbetween the Compton scattered emission and transmitted continuum, indicative oftime lags between the primary X-ray source and reprocessing gas. We predictthat the Fe K$\alpha$ line will respond to the decrease in AGN flux, whichwould manifest as a decrease in the Fe K$\alpha$ EW.

Insight Into "Changing-Look" AGN Mrk 1018 from the Fe K$\alpha$ Line: The Reprocessing Gas Has Yet to Fully Respond to the Fading of the AGN