11i :What is the impact in AP module for changing new Setup Book?

We are changing our accounting calendar periods from APR-MAR to JAN-DEC. So that we create a new calendar, with the correct periods, and define a new set of books that uses new calendar and existing chart of accounts. We will use Consolidation process to move balances from the existing set of book to the new set of book.What the implication in the AP module? What is the implication in the open and partially closed transactions?
Please provide the steps to do in Payables module for setup book changes.