The Collaborative International Dictionary of English v.0.48:

Transmigrate \Trans"mi*grate\, v. i. [imp. & p. p.
   Transmigrated; p. pr. & vb. n. Transmigrating.] [L.
   transmigrare, transmigratum; trans across + migrare to
   migrate. See Migrate.]
   1. To pass from one country or jurisdiction to another for
      the purpose of residence, as men or families; to migrate.
      [1913 Webster]

   2. To pass from one body or condition into another.
      [1913 Webster]

            Their may transmigrate into each other. --Howell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

transmigrate
    v 1: be born anew in another body after death; "Hindus believe
         that we transmigrate" [syn: reincarnate, transmigrate]
    2: move from one country or region to another and settle there;
       "Many Germans migrated to South America in the mid-19th
       century"; "This tribe transmigrated many times over the
       centuries" [syn: migrate, transmigrate]