Hey Denis its me again

As far as I know on the patterns you can modify any track you want, its not an internal style so you don't have to copy it anywhere.
Dano I think you are talking about modifying an internal style (not pattern) in which case you would want to copy it to a CUSTOM style slot then modify, right?

If you mean to modify the bass line without actually erasing the bass line itself (like adding a note or two to what already exists) I will have to check into that, but I would hope so, that is basic sequencing feature that better exist in the X1.