code: public void migrateTo(DTMManager mgr)
     {
       m_mgr = mgr;
       if(mgr instanceof DTMManagerDefault)
         m_mgrDefault=(DTMManagerDefault)mgr;     
     }
docs: Migrate a DTM built with an old DTMManager to a new DTMManager.
  After the migration, the new DTMManager will treat the DTM as
  one that is built by itself.
  This is used to support DTM sharing between multiple transformations.
  @param mgr the DTMManager