The Collaborative International Dictionary of English v.0.48:

desynchronize \desynchronize\, v. t.
   to cause a process to occur at times or in cycles independent
   of another process.
   [PJC] desynchronization

WordNet (r) 3.0 (2006):

desynchronize
    v 1: cause to become desynchronized; cause to occur at unrelated
         times [syn: desynchronize, desynchronise] [ant: sync,
         synchronise, synchronize]