Delete records in routine based on navigational attributes

Hello

In end routine to cube,I would like to delete my RESULT_PACKAGE where atleast one of my 4 navigational attributes TAB1, TAB2, TAB3 and TAB4 of infoobject ZPO_NUM are not blank.

eg., DELETE RESULT_PACKAGE where <TAB1> NE ' ' OR <TAB2> NE ' ' OR <TAB3> NE ' ' OR <TAB4> NE ' '.

How do I refer to my navigational attribute in the routine in order for the above statement to work/?