REPORT  z07_026     .

data : begin of line,
        col1 type i,
        col2 type i,
       end of line.

DATA itab LIKE TABLE OF line.

DO 3 TIMES.
        line-col1 = sy-index.
        line-col2 = sy-index ** 2.
        APPEND line TO itab.
ENDDO.

        line-col1 = '10'.
        line-col2 = '20'.

        MODIFY itab FROM line INDEX 1.

LOOP AT itab INTO line.
        WRITE: / sy-tabix, line-col1, line-col2.
ENDLOOP.

위에 빨간색부분을 추가되면 실행이 되네요.