Hello Vijaya,
If your internal table has only 2 records and if you want to read 2 record having del_ind = 'X'.
Try this
LOOP AT lt_acc INTO ls_acc where del_ind = 'X'.
*"READ TABLE lt_acc INTO ls_acc WItH KEY guid = ls_acc-guid del_ind = 'X'.
*" IF sy-subrc = 0. " here its failing
MOVE ls_acc-zzrks TO ls_acc-zzrks.
MODIFY lt_acc FROM ls_acc.
*"ENDIF.
ENDLOOP.
Thanks
Katrice