What happens when you post to year 2006, when you are in 2007? | SAP-FICO

First of all, to post a document relating to a previous year, say, 2006 when you are in 2007, the relevant posting period should be open' in the system. When such a posting is done, the systen makes some adjustments on the background:
One: the carry forward balances of the current year, already done, are updated in case the posting is affecting balance sheet items.
Two: if the posting is going to affect the Profit & Loss accounts, then the system adjusts the carries forward profit or loss balances to the Retained Earnings account(s).