Yes! You can click on a via point (or a new one you’ve added) at the place where you want to shorten the route.

Choose the little grey ‘…’ icon in the bottom right of the pop-up bubble, and more options will appear. Select ‘Delete before’ or ‘Delete after’. It’ll remove all the via points before/after that location.

Note that a pre-planned route can sometimes change a little after editing, so you might want to review the rest of the route to check that it’s still on course.