Ex. 32:14 (KJV) "And the Lord repented of the evil which he thought to do unto his people" can also be read as "And the Lord relented from the harm which he thought to do unto his people". In 32:12, Moses asks God to "Turn from thy fierce wrath, and relent of this evil against thy people", which can also be read "...and relent from this harm against thy people".
In Num. 23:18,19, just before making his third prophecy, Balaam tells Balak "Rise up, Balak, and hear; hearken unto me, thou son of Zippor: God is not a man, that he should lie, neither the son of man, that he should repent: hath he said, and shall he not do it? Or hath he spoken, and shall he not make it good?
In 1 Sam. 15:11 (KJV), the Lord tells Samuel "It repenteth me that I have set up Saul to be king: for he is turned back from following me, and hath not followed my commandments." This verse can also be read as "I greatly regret that I have set up Saul to be king".
Samuel cites Num. 23:19 in 1 Sam. 15:29, "And also the Strength of Israel will not lie nor repent: for he is not a man, that he should repent."
According to the Matthew Henry Commentary on Num. 23:19:
Men change their minds, and therefore break their words; they lie, because they repent. But God does neither. He never changes his mind, and therefore never recalls his promise. Balaam had owned (v. 8) that he could not alter God’s counsel, and thence he infers here that God himself would not alter it; such is the imperfection of man, and such the perfection of God. It is impossible for God to lie, Heb. 6:18 . And, when in scripture he is said to repent, it is not meant of any change of his mind (for he is in one mind, and who can turn him? ) but only of the change of his way. This is a great truth, that with God there is no variableness nor shadow of turning. Now here, 1. He appeals to Balak himself concerning it: "Hath he said, and shall he not do it? Said it in his own purpose, and shall he not perform it in his providence, according to the counsel of his will? Hath he spoken in his word, in his promise, and shall he not make it good? Can we think otherwise of God than that he is unchangeably one with himself and true to his word? All his decrees are unalterable, and all his promises inviolable.’’ 2. He applies this general truth to the case in hand (v. 20); He hath blessed and I cannot reverse it, that is, "I cannot prevail with him to reverse it.’’ Israel were of old a blessed people, a seed that the Lord had blessed; the blessing of Abraham came upon them; they were born under the blessing of the covenant, and born to the blessing of Canaan, and therefore they could not be cursed, unless you could suppose that the God of eternal truth should break his word, and become false to himself and his people.Secondly, Because Israel are at present unblamable: he has not beheld iniquity in Jacob