overwriting columns with value with column merge?

Dear all,

I have a table with three fields:

co_no

column1

column2

I try to execute

column1 = column2

using knime node column merge

Properties of node column merge:

primary column: column1

secondary column: column2

Option replace primary and delete secondary is activated.

When column1 is not null, replace is not executed!

But column1 should always be overwritten with column2.

Do I have to delete column1 before executing column merge?

Thanks for help!

BR,

Heinz