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We report on an X-ray and optical/UV study of eight Broad Absorption Line(BAL) to non-BAL transforming quasars at $z\,\approx\,$1.7-2.2 over 0.29-4.95rest-frame years with at least three spectroscopic epochs for each quasar fromthe SDSS, BOSS, $Gemini$, and ARC 3.5-m telescopes. New $Chandra$ observationsobtained for these objects show their values of $\alpha_{\rm ox}$ and$\Delta{\alpha}_{\rm ox}$, as well as their spectral energy distributions, areconsistent with those of non-BAL quasars. Moreover, our targets have X-rayspectral shapes that are, on average, consistent with weakened absorption withan effective power-law photon index of $\Gamma_{\rmeff}\,=\,1.69^{+0.25}_{-0.25}$. The newer $Gemini$ and ARC 3.5-m spectra revealthat the BAL troughs have remained absent since the BOSS observations where theBAL disappearance was discovered. The X-ray and optical/UV results in tandemare consistent with at least the X-ray absorbing material moving out of theline-of-sight, leaving an X-ray unabsorbed non-BAL quasar. The UV absorbermight have become more highly ionized (in a shielding-gas scenario) or alsomoved out of the line-of-sight (in a wind-clumping scenario).

X-ray and multi-epoch optical/UV investigations of BAL to non-BAL quasar transformations