Hi Ray,
For Genos, PSR-SX models and PSR-S970/770/975/775 there is the "Drum Setup" function:
The Rhythm parts of a preset Style consist of a preset Drum Kit, and each drum sound is assigned to a separate note. You may want to change the sound and the note assignments, or make more detailed settings such as volume balance, effect, etc. By using the Drum Setup function of the Style Creator, you can edit the Rhythm part of a style and save it as to original style.
Unfortunately, CVP models do NOT have such a Drum Setup function. However, you could edit styles in a suitable computer program, e.g. in the PC (Windows) program "MixMaster". If you record songs on the CVP as a MIDI file, you can edit them later on the computer (e.g. also in "MixMaster" or in a DAW like Cubase). However, this requires certain expertise in MIDI file editing.
With Genos and Tyros5 it is possible to edit preset Drum Kits in the Expansion Manager (YEM) and then use the edited drum kit in Styles or MIDI files. Among other things, you can exchange individual Drum Instruments of a specific preset Drum Kit ( also against Drum Instruments of another Drum Kit. Unfortunately, this is NOT possible with CVP models or with PSR-S/SX models.
Best regards,
Chris