Break

The Break Tool lets you break an element into two elements at a given point or at its intersection with another element.

Select the Break tool on the ribbon or press Ctrl + Alt + B.

As soon as you select an eligible element, all potential break points will be highlighted with unfilled circles. This includes all interior points on polylines, splines, or Beziers, and all intersection points with other elements or with guides. As you mouse over any highlighted point, it will become a circle with a dot. Click to break the selected element there.