If you want to keep your existing BPM SC as is, create a new track and make your changes in the new track.
Go to the NWDI Landscape configurator, select your track where your current BPM SC is and click "Save As" to create a new track.
Next, go to the Transport Studio and check in the required build plugins to build the SC.
Go to the assembly tab of the original track and click on "Forward from History" to forward the original BPM SC to the new track
Finally, go to the new track and import the forwarded SC.