Alma 19:33

And it came to pass that when Ammon arose, he also administered unto them, and also did all the servants of Lamoni; and they did all declare unto the people the self-same thing: that their hearts had been changed; that they had no more desire to do evil.

When Ammon rose up, he also taught them. All the servants of Lamoni did too. They all said the same thing to the people. Their hearts had been changed. They did not want to do evil anymore.