Hi Sudheer,
As you described, now entries are collected in an internal table using normal SELECT query.
Next step is to sort and delete adjacent duplicates from internal table as follows...
SORT it_po BY EBELN EBELP ABRUF ascending EINDT descending.
DELETE ADAJCENT DUPLICATES from it_po COMPARING EBELN EBELP ABRUF.
Thanks,
RKP