Suppose you like a pattern, chorus for example but you want a different fill at the ending. If you use the edit play style you can for example add more toms but the toms get spread throughout the whole pattern. To solve this cut the pattern at the last measure and then add the toms to that measure and join to the main part of the pattern. That way you can get a tom fill at the end. You can then tweak this in the grid if you want.
Superior Drummer 3.1.7 EZBass 1.0.5
macOS Mojave 10.14.5
Logic 10.5.1