Agents sometimes perform actions, in particular social actions such as speech acts, on behalf of other agents. For instance, someone may vote on behalf of a sick colleague in a meeting, an agent may bid for a client at an auction, or a spokesperson may speak for another in a press conference. I argue that in some of these cases of proxy action we can truthfully say that the agent represented has acted through their representative. With the help of comparisons with certain forms of shared agency and tool use, I distinguish between these cases of extended agency from those weaker forms of representation. I then consider what a proxy who is engaged in extending the agency of another must do to prevent that other from being, in a particular sense, alienated from the action performed.