FY variant change in Depreciation Area.

Hi All,

We are using following Parallel ledger concept,and we have one fiscal year variant which is year dependent(Z1) used for Leading ledger and USGAAP (Dep.area)purpose and one for non-leading ledger(K1) which is calender year and for STAT dep.area purpose.Here the new requirement is ,business now need year dependent variant (Z1) to be used for STAT dep.areas purpose without making any chnges in ledger wise(Company code Level).When i am trying to do using standard SAP options it is not allowing me to change.Please assist.