Macro to convert excel to R1C1

Add this code in Thisworkbook Code window of the desired workbook

Private Sub Workbook_BeforeClose(Cancel As Boolean)
    Application.ReferenceStyle = xlA1
End Sub

Private Sub Workbook_Open()
    Application.ReferenceStyle = xlR1C1
End Sub

The reference style is application property so the change will affect all open excel workbooks.