I just wanted to share an example of reshaping a path of topology edges (see attachment) with the 10.1 reshape edge / path tool. Please forgive the made up scenario.
In Panel 1 we have some polygons with a selected path we want to reshape. Panel 2 shows the reshaping line we are going to reshape with (using replace sketch) and Panel 3 shows the result just after Finish sketch. Panel 4 hides the reshaping line to just show the modified polygons...
The ability to reshape multiple edges (and trace to select them is new in 10.1). Keep in mind, though, that the selected edges must be connected. It also generally works better if the selected edges do not form a closed ring.
Here are some relevant help topics and I have videos of all our new topology and alignment functionality forthcoming.
So, looking at the pics, you are drawing the arc through the line that is to be reshaped rather than trying to snap to the end point, akin to how we currently use reshape. and then finishing it up by crossing the line.
Right, you sketch just like you would before. You don't necessarily have to snap the reshape sketch line, it just has to cross twice. Only difference to before is that, technically, there may be multiple edges selected. Since the selected edges are all connected, they just look like one long edge.