Two points:
1) The depreciation does not increase the basis, it lowers it. You have already had a tax advantage from taking it, so at the time of sale, it will give you a larger gain. Also, land is not depreciated. All the depreciation belongs to the building.
2) As @RobertB4444 stated, "So you need to sell the old asset at a loss (received $0 in the sale). So you need to keep the asset in the program to show the sale. Do not delete it now.
