  We present a broadband X-ray study ($\sim$\,0.3-50 keV) of the dwarf nova SS
Cyg highlighting the changes in the accretion during two phases, the quiescence
and the outburst states. The investigation was based on simultaneous
observations carried out with the XMM-Newton and NuSTAR telescopes in two
epochs, involving medium and high-resolution spectroscopy. Spectra were harder
during quiescence ($kT_{\rm high}\sim22.8$ keV) than outburst ($kT_{\rm
high}\sim8.4$ keV), while the mass accretion rate increased by $\sim35$ times
in outburst ($1.7\times10^{16} \rm g\;s^{-1}$) than quiescence. The bolometric
luminosity (0.01-100.0 keV) during the outburst was dominated by a blackbody
emission ($kT_{\rm BB}\sim28$ eV) from the optically thick boundary layer, and
the inner edge of the accretion disk resides very close to the WD surface.
X-rays from the accretion disk boundary layer are consistent with the white
dwarf having mass $1.18_{-0.01}^{+0.02} \rm M_{\odot}$. Our study conclusively
confirms the presence of the reflection hump in the 10-30 keV range for both
phases, which arises when X-ray photons hit colder material and undergo Compton
scattering. We estimated a similarly strong reflection amplitude during
quiescence ($\sim1.25$) and outburst ($\sim1.31$), indicating both the WD
surface and disk are contributing to reflection. The neutral Fe K$_{\alpha}$
line, which is correlated with Compton reflection, also showed similar strength
($\sim80$ eV) in both phases. Finally, X-rays also revealed the presence of a
partial intrinsic absorber during the outburst, possibly due to an outflowing
accretion disk wind.
