Changing Accounting Periods

Hello -

I have a client who created a 13 accounting periods for 2011 (beginning 12/25/10), posted transactions and now wishes to switch to a 12 month calendar year. Obviously, if the periods are not closed (which they are not), NAV will allow us to delete and re-create them.

What I need to understand is what (if any) repercussions are there if I advise this client to delete and recreate an active fiscal year? They already understand that their comparison reporting will be off. They have been live since July, they are not public and have not "hard" closed a single month in NAV yet.

Just want to be safe ...

Thanks!