Dear Prasad,
1. Are you sure the you are selecting 2 record ?
2. Why don't you try delete second record & recreate the same record with 01.08.2015 ?
3. While It's accepted by delimiting the record but now how It's not accepted to change the record ? I think so you might have selected first record so go to PO13 and click on overview button then select & 2nd record then do the change..!
If you will send the screen shot that will be more understand to us where we will give perfect answer..!
