At the moment this is difficult. I have to disable the link which doesn't work quite well many times. "Detour" seems to have vanished but wasn't really good, either.
It would be better to just BLOCK the next step/part of the route I'm following. In a traffic situation I'm often confronted with sudden road blocks and thusfor I cannot follow the route any longer. My good (very) old electronic Navigon device does that. Standard length could be 500 m.
The trick with the link has the disadvantage that the pixel touched is the wrong one and then navigator outsmarts me. Often it blocks the wrong direction of a 4-lane street.
To get the "detour" at the bottom I have to use the first screen with th arrow. Then I get 2 more decisons to answer. In the test situations I didn't get a useful route. 500 m turned out to be too long. 100 m would be better.
I often have the same problem Gaspar mentioned: Suddenly standing in front of a blocked road without any possibility to move on.
MFN offers “detour” with starting options “first junction”, 500 m, 1 km and 5 km, but there is no option to start detour immediately (0 m), that means turn around and drive back until there is another possible route.