  Past X-ray observations of the nearby luminous quasar PDS 456 (at $z=0.184$)
have revealed a wide angle accretion disk wind (Nardini et al. 2015), with an
outflow velocity of $\sim-0.25c$, as observed through observations of its
blue-shifted iron K-shell absorption line profile. Here we present three new
XMM-Newton observations of PDS 456; one in September 2018 where the quasar was
bright and featureless, and two in September 2019, 22 days apart, occurring
when the quasar was five times fainter and where strong blue-shifted lines from
the wind were present. During the second September 2019 observation, three
broad ($\sigma=3000$ km s$^{-1}$) absorption lines were resolved in the high
resolution RGS spectrum, which are identified with blue-shifted OVIII
Ly$\alpha$, NeIX He$\alpha$ and NeX Ly$\alpha$. The outflow velocity of this
soft X-ray absorber was found to be $v/c=-0.258\pm0.003$, fully consistent with
iron K absorber with $v/c=-0.261\pm0.007$. The ionization parameter and column
density of the soft X-ray component ($\log\xi=3.4$, $N_{\rm H}=2\times10^{21}$
cm$^{-2}$) outflow was lower by about two orders of magnitude, when compared to
the high ionization wind at iron K ($\log\xi=5$, $N_{\rm H}=7\times10^{23}$
cm$^{-2}$). Substantial variability was seen in the soft X-ray absorber between
the 2019 observations, declining from $N_{\rm H}=10^{23}$ cm$^{-2}$ to $N_{\rm
H}=10^{21}$ cm$^{-2}$ over 20 days, while the iron K component was remarkably
stable. We conclude that the soft X-ray wind may originate from an
inhomogeneous wind streamline passing across the line of sight and which due to
its lower ionization, is located further from the black hole, on parsec scales,
than the innermost disk wind.
