If you're using depreciation books, you can change the depreciation conventions for a group of assets that are part of the same depreciation book. For example, if you are in the United States and you placed more than 40 percent of your assets in service during the fourth quarter of the year, you must use the mid-quarter depreciation convention. You can use the mass update process to change all assets that require the new depreciation convention

When you update the depreciation convention for assets, existing depreciation transactions, depreciation adjustment transactions, bonus depreciation transactions, and extraordinary depreciation transactions that exist for those assets are deleted.

To update the depreciation convention for assets that have already been disposed of, you must first delete existing disposal transactions, including transactions that were generated because of the disposal process.

Then you can process depreciation and extraordinary depreciation for each asset and make manual depreciation adjustments, if necessary.