I'd like to expand on this a bit (perhaps Mikhail can translate),

RealTracks cannot be edited in the same way that MIDI tracks can be. With MIDI, you can open the Notation window and edit any of the individual notes (change the pitch etc.). If you don't regenerate the arrangement (i.e. the track is frozen) or if you are editing the Melody or Soloist track then when you play it back it will play the new notes. This is because with MIDI data, Band-in-a-Box is sending the MIDI event data to a synthesizer that generates the audio and plays the notes.

A track with RealTracks on the other hand is audio (wave) data that is assembled from actual audio recordings of musicians. You may still be able to SEE the notes in the notation window (or Piano roll), but you can't change them. You can see them because some RealTracks have "RealCharts", which means that the performances have been manually transcribed as MIDI so that the notation can be displayed.

I'm not sure what you are trying to achieve (what types of edits you want to do), but there are a couple things you can do. It is best to do this in a DAW (e.g. RealBand which ships with Band-in-a-Box), or another DAW using the Band-in-a-Box plugin if you have version 2019. RealBand (and also the DAW plugin) has a "multi-riffs" feature which allows you to regenerate a specified region of a track, and choose from several different generations. You can save your song (.SGU) and open it with RealBand. This is handy if you mostly like the generated part, but there are a few bars that don't sound good.

There are also ways you can edit the audio waveform data to some extent, for example copying/deleting certain sections. You can even change the pitch with some DAWs, but you can't necessarily edit individual note pitches unless it was a truly monophonic recording (one note at a time).
PG Music Inc.