White shell work is a term used by commercial real estate holding companies. It involves returning a commercial space back to an empty blank canvas. This usually involves cutting, capping, making safe of mechanical, electrical and plumbing systems, removal of all interior components back to the building envelope.
It can also involve re-demising a large space into a series of smaller spaces. A white shell project will usually involve a complete interior gut out, mechanical, electrical, plumbing reconfigurations, framing and drywall and painting.