Bonus Depreciation

Hi,

I would like to know how to back out from bonus depreciation. We are planning to set bonus rule for assets. Now say we depreciate with the bonus rule for the assets first half of its lfe (from JAN to JUN). In the beggining of July, it is decided this asset should not have the bonus depreciation for this year. In this case, how easy it will be to back out of bonus depreciation and correctly recalculate the depreciation for that asset in that whole year.

An example - I have an asset 'A'. I set a bonus depreciation rule for 20% of this year. I ran depreciation for six months. Each month total depreciation was calcuated - normal depreciation (say $100) plus bonus depreciation (say $20). Then starting on 7th month, I changed the bonus rate to 0. Then ran depreciation and total depreciation calculated as $100. What we want is to calcuate the depreciation as if there was no bonus depreciation from the begining for the year. Is it possible?