Going back on something is an act of breaking a promise or reneging on an agreement. Some common synonyms for this phrase include breaking, violating, reneging, defaulting, and betraying. Breaking implies a complete disregard for the promise made, while violating suggests a wilful breach of a legal obligation. Reneging implies retracting from a commitment, while defaulting refers to a failure to fulfill an obligation. Betraying suggests a breach of trust or loyalty. Other phrases that can be used include backing out, reconsidering, or changing one's mind. Ultimately, whatever phrase is used, going back on a promise can damage trust and relationships.