Try

SELECT * ;
  FROM lineitem t1 ;
  WHERE RecType = "A" ;
    AND EXISTS ( SELECT * ;
			FROM lineitem t2 ;
			WHERE RecType = "I" ;
				AND t2.ParentId = t1.ParentId ;
				AND t2.LineId = t1.LineId ) ;
UNION ALL ;	
...

>Wow! Worked perfect. One thing though - it's pulling both records that
>have had a modification AND those that have not.
>
>I only want the records that have had a change, and the previous
>record for it.