Right, at this time it is not possible to change RealTrack instruments in the middle of a song. You could, however, put the same instrument on two tracks and use different styles with each, and mute one or the other using F5 where you wish. I think that's one of the suggestions jazzmandan was describing.

Since you mention C/D, you probably mean MIDI styles and yes, those can change within a song, but you will only hear a difference if the style was programmed to give one. Many styles only feature A and B substyles. The use of C and D or more depends on what that style was programmed to sound like. You can also modify MIDI styles and save copies under a different name, if you like.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.