  Multi-epoch XMM-Newton spectra of the two Narrow Line Seyfert 1 (NLS1), Mrk
478 and EXO 1346.2+2645, are presented. The data were fitted with different
models, including the relativistically-blurred reflection model reflionx, which
was found to give a good description of both spectra in all epochs. The two
sources are reflection dominated with the illuminating continuum hidden from
view. This can be explained either in terms of a corrugated disc or strong
gravitational light bending effects. The emission from these two sources comes
from a very small region (few gravitational radii), very close to a rapidly
spinning black hole.
  Spectral variability analysis show that both sources have constant RMS
spectra, and constant hardness ratios in all epochs, in agreement with a single
spectral component. The constancy the spectrum between high and low states
rules out alternative models such as partial covering.
