When looking for antonyms for "changed one's mind," one could consider words like resolute, unwavering, or steadfast. These terms suggest a firmness of purpose or decision that remains unwavering despite any external factors or influences. Other antonyms might include unyielding, determined, or decisive. These words convey a sense of certainty and conviction, indicating that the individual in question has made a choice and is sticking to it, regardless of any obstacles or challenges that may arise. Ultimately, the antonyms for "changed one's mind" highlight the importance of being committed to one's beliefs and values, and of standing firm in the face of adversity.