To deputize

To deputize - to give someone the power to do something in place of another person.

Example - "I deputize for the newspaper's editor on the weekends"

Image - http://www.azquotes.com/picture-quotes/quote-don-t-wait-for-anyone-to-deputize-you-or-authorize-you-or-empower-you-you-have-to-just-hazel-henderson-70-14-80.jpg