This inaugural post on Unspotted is a dope dive into a few specific times Kanye West flipped the meaning of sampled vocals:

10 Times Kanye West Changed the Meaning of a Sample.

The author breaks down how each vocal was flipped, whether by suggesting the lyrics to us via the songs' titles, or by actually layering additional vocals on top.

My favorite flip is personally "Late" because it required the most chopping/tweaking of all of them. Check the article for more details.

Peep it in video form here as well:

Hat tip to the post by the author themselves on r/hiphopheads.

Update: The author also made a dope J. Dilla post and video: