Renunciation
noun
rejecting or disowning or disclaiming as invalid
“Congressional repudiation of the treaty that the President had negotiated”
Similar: repudiation
noun
the state of having rejected your religious beliefs or your political party or a cause (often in favor of opposing beliefs or causes)
Similar: apostasy, defection
noun
an act (spoken or written) declaring that something is surrendered or disowned
Similar: renouncement