WARNING: This page is about a different car, the 2010 Porsche Cayenne, 2009 Porsche Cayenne, and 2008 Porsche Cayenne. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Overview Of Passenger's Sockets
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Release -a-
and pull off plug.
Fig 2: Pulling Plug Off Passenger's Socket
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Open socket cover and press out the passenger's socket -arrow-
.