1. 1934 Indian Reorganization Act: This act reversed some of the Dawes Act's provisions and allowed tribes to re-establish their governments and reclaim some of their land. This marked a significant shift in policy towards Native American self-governance.
2. 1946: The Allotment Act was formally amended, halting further allotments of land to individual Native Americans. This effectively ended the process of breaking up tribal lands.
3. Ongoing Legal Challenges: Various legal challenges and court decisions over the years helped to further diminish the act's effects.
Therefore, while there's no single ending date, the Dawes Act's influence and impact waned gradually over time due to these key events. The 1934 Indian Reorganization Act is considered the most significant turning point in shifting away from the Dawes Act's policies.