Display internal tables data in alv grid

Hi Abapers,

I have two internal tables itab1 and itab2. where itab1 contains old data and itab2 contains new changed data in alv editable grid.

now i have to insert itab2 data in ztable and display itab1 and itab2 data in alv grid output when data is changed and clicked SAVE.

I am not able to display and insert.

Thanks & regards.