renunciation - noun

rejecting or disowning or disclaiming as invalid

the state of having rejected your religious beliefs or your political party or a cause (often in favor of opposing beliefs or causes)

an act (spoken or written) declaring that something is surrendered or disowned

the act of renouncing; sacrificing or giving up or surrendering (a possession or right or title or privilege etc.)

renunciation - thesaurus

apostasy   defection   forgoing   forswearing   renouncement   repudiation