changed Parent of TotalOpeningBalance to other member, which is created outside FCCS_Mvmnt hierarchy

Mistakenly changed the Parent of Total Opening Balance from FCCS_Closing Balance to some other member, which is created outside of FCCS_Movements hierarchy. Now when trying to change it back to FCCS_ClosingBalance, system isn't alowing?

Intent was to share the Total Opening Balance but mistakenly changed the parent itself.

Kindly need help to revert the situation back.