Source : Webster's Revised Unabridged Dictionary (1913)

Deputize \Dep"u*tize\, v. t.
   To appoint as one's deputy; to empower to act in one's stead;
   to depute.

Source : WordNet®

deputize
     v 1: act as a substitute; "She stood in for the soprano who
          suffered from a cold" [syn: {substitute}, {deputise}, {step
          in}]
     2: appoint as a substitute [syn: {depute}, {deputise}]