4/30 Fiscal Year Bonus Depreciation Not taken on 01/01-04/30 Assets and Tax Books Closed

We are a 4/30 year end corporation that filed its 2013 Tax return claiming bonus depreciation only on assets placed in service From 05/1-12/31/13.  Depreciation has been run for our tax books (federal, state, & AMT) and each period was closed thru the year ended 05/30/14.  Now that congress has extended bonus depreciation through 12/31/14, the assets we placed in service from 01/01/14-04/30/14 should have bonus depreciation taken on them.  How do make these changes to closed periods so that the full amount of allowable bonus depreciation is captured as of 04/30/14 and the 2nd year of depreciation is recalculated