  We present results from two XMM-Newton observations of the bright classical
Seyfert 2 galaxy NGC 7582 taken four years apart (2001 May and 2005 April). We
present the analysis of the high-resolution (0.3-1 keV) RGS and low-resolution
(0.3-10 keV) EPIC spectroscopic data. A comparison with a 1998 BeppoSAX
observation suggests that XMM-Newton caught the source in a
`reflection-dominated' phase, measuring the lowest continuum flux level ever
(F(2-10 keV) = 2.3 x 10^(-12) erg cm^-2 s^-1) in 2005. NGC 7582 therefore
experienced a dramatic spectral transition most likely due to the partial
switching-off of the nuclear activity. The XMM-Newton spectrum of the continuum
emission is very complex. It can be well described by a model consisting of a
combination of a heavily absorbed (Nh ~ 10^(24) cm^-2) power law and a pure
reflection component both obscured by a column density of ~ 4 x 10^(22) cm^-2.
Notably, we detect a significant increase by a factor of ~2 in the column
density of the inner, thicker absorber covering the primary X-ray source
between 2001 and 2005. The 2005 XMM-Newton spectra show the strongest Fe Kalpha
emission line ever measured in this source. This is consistent with the line
delayed time response to the decrease of the nuclear activity. Our analysis
also reveals that the soft X-ray spectrum is dominated by emission lines from
highly ionized metals. The detection of a narrow OVIII radiative recombination
continuum suggests an origin in a photoionized plasma.
