With influence arrows, you can change the route taken by the arrow. Simply drag any part of the arrow, and the whole arrow will be redrawn along a new curve.
Where an influence arrow is broken into several segments, as it traverses submodel boundaries, each segment is treated independently. Thus, dragging one segment only affects that segment. Dragging a node at the start or end of the influence arrow likewise only affects the first or last segment.
You can move the dot where the influence arrow crosses a submodel boundary. This changes only the two segments that enter or leave the dot. Click on the dot or on the arrow head connected to it, and drag around the boundary. It can be quite hard to select the dot/arrowhead for moving rather than the link shaft on either side.
In: Contents >> Working with model diagrams >> Moving model diagram elements