I know this is an old thread, but maybe you can help me. I discovered the same thing. My new client has a rental property that has a cost basis that includes the land value. It has been depreciated since 2012. Do I just change the amount of depreciation to the correct amount in the current year, or am I stuck with the cost basis that was filed for originally? The IRS gets their taxes back when the house is sold, so I don't think I need to amend prior year returns. Since form 3115 can't be used, I'm not sure what that means.... any help is appreciated.