GL Unpost Question

Background: A foreign company was set up in late 2010; A new Business Unit and Department (we call it cost center).  After auditors reviewed the financials for 2011, it was determined that many of the expenses could not be charged to that company, but should have been charged at the parent company level, or into another ‘Admin’ cost center/department.  So to get the financials correct the users want to basically ‘undo’ what should not have been posted and then re-post the journals correctly. 

Because of my limited financial experience, I asked my question on an online IT website and the ‘Unpost Journal Process’ was offered as a possible solution.