God can change His mind (relent, repent).
In some things He will not: " For the gifts and calling of God are without repentance." ~Rom 11:29; ?" (For those priests were made without an oath; but this with an oath by him that said unto him, The Lord sware and will not repent, Thou art a priest for ever after the order of Melchisedec:)" ~Heb 7:21
In other cases, the Lord repented (Hebrew: nacham - NOT repentance of sin, but to be sorry or have a change of mind). " And Samuel came no more to see Saul until the day of his death: nevertheless Samuel mourned for Saul: and the LORD repented (nacham) that he had made Saul king over Israel. ?" T he Lord repenting for making Saul king does not constitute God making an error. The Scriptures say, " Only fear the LORD, and serve him in truth with all your heart: for consider how great things he hath done for you. But if ye shall still do wickedly, ye shall be consumed, both ye and your king." ~1 Sam 12:24,25. And later, Samuel spoke to Saul saying, " Thou hast done foolishly: thou hast not kept the commandment of the LORD thy God, which he commanded thee: for now would the LORD have established thy kingdom upon Israel for ever. But now thy kingdom shall not continue: the LORD hath sought him a man after his own heart, and the LORD hath commanded him to be captain over his people, because thou hast not kept that which the LORD commanded thee. ?" ~1 Sam 13:13-14. Saul did not keep the Lord's command and did wickedly. There was a consequence for it and Saul and the people were warned in advance.
As God’s prophet Jonah preached to Nineveh, “… God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them …” ~ Jonah 3:10 . In such instances, God “repented,” or changed His mind, to bring about a change of plan.
In many cases, God repented of the wrath He was going to bestow on a disobedient recipient or recipients. That doesn't make Him lesser of a God, but merciful (read the account of a certain king in Matt 18:21-35).
It would seem that some here think that because God can change His mind, it makes Him imperfect or indecisive. That's not the case at all. God has every right to change His mind and repenting of something does not necessarily mean the one repenting has sinned. This is quite obvious in God's case since God by nature cannot sin.