How can God change His mind? The text in Genesis seems to indicate that He has.

And the LORD was sorry that He had made humankind on the earth, and He was grieved in His heart (Gen 6:6).

This is another example of the Bible expressing God's feelings in language that we as humans can understand. Human characteristics are ascribed to God so that we can better understand the situation. The Bible says that God is unchangeable in His character.

For I am the LORD, I do not change; Therefore you are not consumed, O sons of Jacob (Mal 3:6).

Therefore the Lord does not second guess Himself. He did not change His mind. God was grieved in the sense that humankind, with all his possibilities, had become engrossed in sin. Of course God knew this would happen, since He is all-knowing. Nevertheless, for our benefit, this statement about God's feelings is recorded.