How do I change the horn on the JCornell's GP38-2?

Hello everyone.
I want to change the horn that the BNSF one has to the one the NS one has. The reason for this is because my one NS engine (downloaded from Digirail with a light upgrade) has the BNSF horn. I much prefer the one on the NS GP38 because it sounds better in my opinion.
I want to change the horn that the BNSF one has to the one the NS one has. The reason for this is because my one NS engine (downloaded from Digirail with a light upgrade) has the BNSF horn. I much prefer the one on the NS GP38 because it sounds better in my opinion.