Ah, got it.

You essentially need to tell the program it was converted to personal use, and there should not be any business gain or loss.  I don't use Lacerte, so perhaps somebody else can give specifics for that, but in ProSeries you enter the sale date but leave the sale price BLANK.  Or in your case, there is no need for it be on the depreciation schedule at all, so you could just delete it.

Then just make a regular charitable contribution on Schedule A.