renegeotiate
To unfeelingly yank da rug out from under somebody who's already agreed to your terms, while selfishly/invalidly packaging said flimflammery-fiasco as a necessary "we need to talk" alteration.
Da tiger promised da Brahman dat he wouldn't eat him if he let him outta da cage, but then he renegeotiated said promise and thus forced said naive trusting soul to try to get some other living creature to agree with him dat da tiger was doing da wrong thing.