WARNING: This page is about a different car, the 2011 Subaru Tribeca. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect the ground cable from the battery.
Remove the luggage room light body (A).
Fig 1: Removing Luggage Room Light Body
Courtesy of SUBARU OF AMERICA, INC.
Disconnect the harness connector and remove the lens.