The fundamental definition of a REIT is a matter of corporate structure and charter. PZN became a REIT in the last reorganization, and will remain so until the shareholders vote to make a change, if they do.
This is not to be confused with qualifying for special tax benefits only available to REITs. PZN has failed to meet those standards, and will as a result be taxed the same way a c-corp is taxed.
Another way to look at this is that the IRS determines whether and how PZN is taxed, but only the shareholders determine corporate structure. PZN ***may*** be a REIT without the tax benefits of retaining that type of corporate organization.