Add update calendar from 12 month to 13 months

Hello All,

We are on 12.1.3 our calendar type is 'Month 12 Calendar' we want to add Months 13 to use 1 month as Adjustment period.

Please advise.

Now our setup is:

Month 12 Calendars

Quarter 4 Fiscal

Week 53 Calendar

Year 1 Fiscal

Thank You

SD