Select the track name you want to change
Put the cursor on the bar where you want to make the change
Click the bar once (to highlight it)
Right click and select Bar Settings for Bar#
Select the track name you want
In the panel the opens, select the chorus number where you want the change to occur (drop-down box at top)
Then, near the top (under the Chorus drop-down) you'll see STY button, select it
Select the style you want...

You'll need to do this again where you want to change back to samba...

Works fine for me. But, I will say that this is not user friendly (BIAB folks appear to like holding on to legacy methods).
The best thing you can do for yourself is to make a spreadsheet of tracks, chouses... and write the changes down because there is no way of looking to see what you have (not at all user friendly