itab1 to itab2

hi,

i am having values in one itab1.in another itab2 i am having same fields plus few extra fields with values.i want to move the values in first itab to itab2.

when i used this query i am not getting values in itab2.

loop at itab1.

move-corresponding wa1 to wa2.

modify itab2 from wa2 transporting .....

endloop.

if anyone knows kindly help me.thanks in advance.