I am trying to use modify but my zzxmnga does not get updated but when i debug it has the correct value in it but doens't modify the record. Here is the code
LOOP AT T_ZOXED10166 INTO W_ZOXED10166.
wa_TABIX = SY-TABIX.
READ TABLE T3_ZOXED10166 INTO W3_ZOXED10166 WITH KEY
RUECK = W_ZOXED10166-RUECK
GRUND = W_ZOXED10166-GRUND.
IF SY-SUBRC = 0
AND W_ZOXED10166-GRUND+1(1) CP 'S'.
W3_ZOXED10166-ZZXMNGA = W_ZOXED10166-XMNGA + W3_ZOXED10166-XMNGA.
MODIFY T3_ZOXED10166 FROM W3_ZOXED10166 INDEX WA_TABIX.