>>For this select you don't need SELECT IN clause at all. Just add your WHERE condition to the Select statement.
>>
>I don't think so. I need all the records for any RMA which has a record of "Passed - waiting for source". Removing the IN clause would throw away those other records
>

>>>SELECT * FROM (lcReturn) ;
>>> WHERE rma_no IN (SELECT rma_no FROM (lcReturn);
>>>                   WHERE activity = "Passed - waiting for source" ;
>>>                    AND EMPTY(date_end)) ;
>>>  INTO CURSOR (lcReturn)

is the same as

SELECT * FROM (lcReturn) ;
 WHERE activity = "Passed - waiting for source" ;
                    AND EMPTY(date_end)) ;
  INTO CURSOR (lcReturn)