1. When navigating tap on the map. You get a window, which asks you to confirm the distance to the obstacle. A second screen asks you to confirm the length of the obstacle. After having done this, you will get an new route.
2. For tomtom maps I don't know. But you will have to report any changes via the tomtom website and afterwards buy a (discounted) new map update from Mapfactor (check the date of map data!).
OSM maps are basically updated once a month. You may change OSM data at openstreetmap.org and will get your change (depending on processing dates) upon the free download of new maps within two months at the latest.