WordNet (r) 3.0 (2006):

switch over
    v 1: change over, change around, as to a new order or sequence
         [syn: switch over, switch, exchange]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "switch over":
   about-face, alchemy, assimilation, assumption, becoming, change,
   change-over, conversion, flip-flop, growth, lapse, naturalization,
   passage, progress, re-formation, reconversion, reduction,
   resolution, reversal, shift, switch, transformation, transit,
   transition, turning into, volte-face