The closest thing to ending colonialism in countries like the U.S. and Canada would be if non-Natives chose to respect the land and Indigenous people. Americans and Canadians who are not of Indigenous ancestry cannot be expected to just vacate the premises. What they can do, however, is understand that they may call North America home but it's still stolen land. They need to respect Native traditions, stop deforestation, quit wearing headdresses, only buy Native goods from Native vendors, etcetera. Basically, non-Indigenous Americans and Canadians NEED TO choose to be good neighbors (and I say that as a white person with actual colonizers in her family tree).