Can an all-knowing God change his mind? Does that make sense?

Consider 1 Chronicles 21:14-15:

The Lord sent a plague on Israel, and seventy thousand men fell dead. And God sent an angel to destroy Jerusalem. But as the angel was doing so, the Lord saw it and relented and said to the angel who was destroying the people, “Enough!”

God makes a decision but changes his mind?

The problem with God changing his mind in the Bible is that it goes against the common assumption that God knows everything, including the future.

An omniscient being incapable of making mistakes does not make decisions that need to be reversed.

1 Chronicles 21:14-15 (New International Version)