deputize

verb3

1. •
   To officially empower, authorize, pronounce, and establish (someone) to be a deputy.
2. •
   to officially empower and authorize (someone) to act as a substitute in one's role or office

   • I deputize you to act for me while I'm away.
3. •
   To act as a substitute for a person in their role or office

   • Gringoire, on the other hand, stuck with equal firmness to the fact that he was deputizing for a brother officer who was sick — so sick that he had mislaid his orders. — 1929