Depreciation correction on duplex

[John Noble]

Owner occupied duplex. 50% rental, 50% owner occupied. $100K home. $40K basis for depreciation. Moved out 5 years later = 100% rental. Problem = I just kept going on the same depreciation schedule but listing the depreciation basis at $80K and took the full depreciation % for year 5. I also did the same with depreciating siding, but at 20HY 150DB. And then I did it all again with another property. Many years later, I now wish to use online tax software, but it will explode out each half unit as its own property (as it should have been originally). Now I’m trying to fix without making a paperwork mess. Thoughts?