Buying rental properties that are currently in a C corp

I'm negotiating with a seller that has a few properties on different parcels that were transferred years ago into a C corporation. We're discussing ways to execute a sale, an owner carry is optimal but the problem she faces is that a sale would end up causing a double taxation to her. If I buy the corporation that burden ultimately falls to me and I plan on selling a few of the properties within a couple of years after rehab and rent stabilization. 

Is there a way for the seller to extricate herself from the corp and only get taxed once? Or what strategies would you employ to reduce the tax burden on the seller while not transferring them to me?