We can edit the map with rtabmap-databaseViewer, see
http://official-rtab-map-forum.206.s1.nabble.com/post-processing-manually-add-obstacles-to-map-tp6985p6993.htmlIf you want the robot to update the map, it should be restarted in SLAM mode. You can enable Rtabmap/StartNewMapOnLoopClosure to start updating the map only after the robot has been localized with the map already in the database. I would call this mode "Append Mode".
cheers,
Mathieu