Sorry for the delay - month end got in the way.
This is what I was told by our GP VAR:
Change the Current Year End Date - in our case Dec 31 to Dec 30.
Calculate - GP will recalculate the periods for the current year.
I changed the period start dates back to Jan 1, Feb 1, Mar 1, etc. I didn't calculate I just clicked OK. (The reason I set the period start dates back to the 1ST of each period was to keep CM, AP & AR in sync with the GL). GP gives you a warning message but I said okay.
I then set up the new Fiscal Year - Start Date = Dec 31, 2013; End Date = Dec 29, 2014; Periods = 12, the click Calc. GP creates it's own period start date for each period; I overrode those dates with our own. Again clicked OK not Calc, GP gave me a warning message, clicked OK and the 2014 Fiscal Calendar is set.