@sudolea Moving multiple waypoints simultaneously is not possible at the moment... And I even feel like this is not the intention of TS but maybe I'm wrong?
Instead I think TS refers to the fact that somebody further down the route can catch on from there and not have to go through the hassle of either deleting all wp up to that location or skipping the wp up to that location. (Reading again my own post already is quite MRA Navigation "heavy" haha. Since other gps devices do not use WP driven routes but instead navigate by using tracks.)
The destination of the route will probably not be any different between both persons so it's only about deleting the unnecessary wp for other users other than the ones they start at wp 1.
With MRA Navigation one can start the navigation from the nearest waypoint so deleting any previous ones relative tot the current position in the route (i.e. wp5 instead of wp1) is not needed.
At the moment MRA Routpelanner offers the option to set any WP in the route to be the starting wp from the waypoint menu, but that does NOT delete any wp up to the new start point, but instead just renumbers the route. I.e.: a 20 wp route, with start at wp1, will look like: wp1->wp20, but will look like the following when i.e. wp5 is set to be wp1: wp5->wp20:wp1:wp2:wp3:wp4... And then of course renumbers it to become wp1->wp20 again. ... Hope that makes sense... Of the route itself is not to be changed but only the starting wp is to be changed, then this option solves the TS's question... 
️Yet, @PAD-0 was right about the cake stops then. These will of course not be modified accordingly and is simply impossible to facilitate.
But just as @Nick-Carthew said, if one creates a basic account (but of course gold is the way to go 
) they can delete all waypoints up to their location to accommodate exactly what TS wants to facilitate.
