to maybe clarify the calendar conversation, Multi-Calendar is only available in OneWorld accounts. So if @mg2017 has only one legal entity or isn't on OW, using the multi-calendar feature isn't an option. If you have multi-calendar, then it is really easy, but without it, it's tough. I ran into this with a client. we had to move all transactions out of the period in question and then create the new period structure. If you have that many months worth of data, you may just have to create it with the new structure for next year. You can't really change the past.