how to clear Multi COlumn List box

[Mudda]

I have aMulti COlumn List Box Indicator in my program. This list box
is updated while my program is running. When i stop my Program and
start it again with out closing the Window. The new data is appended
to the old data. Is there any way to clear the existing data in the
list box when I start my program and display the new data from the
first row.