  The Galactic microquasar GRS 1915+105 exhibits various types of light curves.
There is, however, no understanding of when a certain type of light curve will
be exhibited and only in a handful of cases, the transitions from one type to
another have actually been observed. We study the detailed spectral properties
in these cases to show that that different classes have different ratio of the
power-law photon and the blackbody photon. Since the power-law photons are from
the Compton cloud, and the intensity of the power-law photon component depends
on the degree of interception of the soft photons by the Compton cloud, we
conclude that not only the accretion rate, but the accretion flow geometry must
also change during a class transition.
