Sometimes you add a loop to your project only to find it's longer than you need it to be. So let's make it shorter! Hover over the top right corner of the looped region to show the loop handle (1). Click with the Loop tool that now appeared and drag to the left to make the loop shorter (2).
In order to make the base region shorter, use the handle in the lower right corner of the region (3). Click and drag to the left to make it shorter (4).
You might want to zoom in, change the grid size or turn off snap to grid mode in order to make finer adjustments. When you're happy with the length, you can use the loop handle again and drag to the right to loop the region.
Pro tip: You can jump straight to the region handle of your base segment and drag to the left while the total number of loops/repetitions will stay the same.
(1) Loop handle
(2) Click and drag from the loop handle to make the region shorter
(3) Region handle
(4) Click and drag region handle to make the region shorter