Use Forms Mode. Open the unwanted K-1 from the California forms list on the left and click the Delete button at the bottom of the screen.
If the K-1 isn't in the Calif forms list, then click the Open Form button above the forms list, expand the California list, scroll down to that K-1 type and open that. You will get a dialog to name the new K-1 but your unwanted K-1 should be in the box at the top of the dialog. Open it from there and then delete it.
