The Collaborative International Dictionary of English v.0.48:

Rebaptize \Re`bap*tize"\ (r[=e]`b[a^]p*t[imac]z"), v. t. [Pref.
   re- + baptize: cf. F. rebaptiser, L. rebaptizare.]
   To baptize again or a second time.
   [1913 Webster]