  At only 90 Mpc, ASASSN-14li is one of the nearest tidal disruption event
(TDE) ever discovered, and because of this, it has been observed by several
observatories at many wavelengths. In this paper, we present new results on
archival XMM-Newton observations, three of which were taken at early times
(within 40 days of the discovery), and three of which were taken at late times,
about one year after the peak. We find that, at early times, in addition to the
~1e5 K blackbody component that dominates the X-ray band, there is evidence for
a broad, P Cygni-like absorption feature at around 0.7 keV in all XMM-Newton
instruments (CCD detectors and grating spectrometers), and that this feature
disappears (or at least diminishes) in the late-time observations. We perform
photoionization modelling with XSTAR and interpret this absorption feature as
blueshifted OVIII, from an ionized outflow with a velocity of 0.2c. As the TDE
transitions from high to low accretion rate, the outflow turns off, thus
explaining the absence of the absorption feature during the late-time
observations.
