Hi @eliyahu100 ,
This code should do it. If the value is not 999, then you can change it to whichever value it needs to check.
Names Default To Here( 1 );
dt = Current Data Table();
For( i = 1, i <= N Rows( dt ), i++,
For( l = 1, l <= N Cols( dt ), l++,
If( Column( l )[i] == 999,
Column( l )[i] = .
)
)
);
Hope this does it!,
DS