DE.PARENTNAME
Syntax
DE.PARENTNAME(Dimension, Element,
          Index)
      
Dimension is the name of the
        dimension. Element is the element name whose parent you
        want to get. Index is the number of the parent.
The arguments Dimension and Element can
        be strings or operations that result in a string. Hardcoded strings must be enclosed in
        single or double straight quotes.  
The argument Index must be a number or an operation that
        results in a number. It can be a number other than 1 if the element occurs several times in
        a hierarchy under different parents. For example, in a hierarchy of regions, a country could
        be a child of both a European Union element and a Central Europe element. 
Example
The Bayern element in the REGION dimension rolls up into the parent, Germany. This example returns Germany:
DE.PARENTNAME('REGION', 'Bayern', 1)