Final answer:
The change in legislation is known as Bill C-31, an amendment to the Indian Act in 1985, addressing gender discrimination and restoring status to Indigenous women who married outside their band.
Step-by-step explanation:
The change in legislation that ensured that no Indigenous woman lost her status through marriage to someone outside her band is known as Bill C-31, an amendment to the Indian Act in 1985. This amendment was part of an ongoing process to address gender discrimination and restore status to those who had lost it due to previous versions of the Indian Act.
The changes were driven by the advocacy of various Indigenous groups and feminists who fought for the equality of Indigenous women in Canada.