In response to the argument of Moses, the Lord changed his mind.
This does not show God as an angry ruler who must be forced to calm down. The Bible does not present him as a tyrant who is difficult to persuade.
Instead, the Lord is more willing to show mercy than to bring punishment. He invites those who are close to him, like Moses, to pray and speak on behalf of others.
Through faithful intercession (prayer on behalf of someone else), God gives an opportunity for mercy.