  We report on X-ray flares that were observed from the active galactic nucleus
I Zwicky 1 (I Zw 1) in 2020 January by the NuSTAR and XMM-Newton observatories.
The X-ray spectrum is well-described by a model comprised of the continuum
emission from the corona and its reflection from the accretion disc around a
rapidly spinning (a > 0.94) black hole. In order to model the broadband
spectrum, it is necessary to account for the variation in ionisation across the
disc. Analysis of the X-ray spectrum in time periods before, during and after
the flares reveal the underlying changes to the corona associated with the
flaring. During the flares, the reflection fraction drops significantly,
consistent with the acceleration of the corona away from the accretion disc. We
find the first evidence that during the X-ray flares, the temperature drops
from 140(-20,+100)keV before to 45(-9,+40)keV during the flares. The profile of
the iron K line reveals the emissivity profile of the accretion disc, showing
it to be illuminated by a compact corona extending no more than 7(-2,+4)rg over
the disc before the flares, but with tentative evidence that the corona expands
as it is accelerated during the flares. Once the flares subsided, the corona
had collapsed to a radius of 6(-2,+2)rg. The rapid timescale of the flares
suggests that they arise within the black-hole magnetosphere rather than in the
accretion disc, and the variation of the corona is consistent with the
continuum arising from the Comptonisation of seed photons from the disc.
