Hello, I would to ask how can I change the coordinate system on basemap/imagery. I can change the coordinate system of all my layers except this one 😞 . Thank you very much in advance
You can set the map's coordinate system to what you want, then add the basemap/imagery and it should project-on-the-fly. Or alternately, add a layer to an empty map which has the coordinate system that you want and make sure the map has been set properly, then add the basemap
Note, that you can't "change" the coordinate system of layers/featureclasses unless you have used the Project Tool in ArcToolbox