Try:
SELECT T0.[DocNum], T0.[ItemCode], T2.[ItemName], sum(T1.[BaseQty])
FROM OWOR T0 INNER JOIN WOR1 T1 ON T0.DocEntry = T1.DocEntry INNER JOIN OITM T2 ON T1.ItemCode = T2.ItemCode
Where T0.[Status] = 'R'
group by T0.[DocNum], T0.[ItemCode], T2.[ItemName]