Possible to edit current KNIME nodes?

Is it possible to edit codes for current KNIME nodes already developed freely from KNIME?
It’s because I want to edit the table filter but don’t want to develop a whole new node that will do what I want when there is a node close to what I want and needs few tweaks to make it do what I want.

Thank you very much.

The source code for all nodes is accessible via the source-plugins in the KNIME SDK. You can derive your own nodes as long as you stick to the license. But you need to write a complete new node, changing the behavior of existing nodes is not possible.