re-form' (yacar): The word in the Revised Version (British and American) is found only in Le 26:23, in the phrase "ye will not be reformed." The meaning is, "to be instructed," or, more fully, "to let one's self be chastened," i.e. by God's discipline to learn the lessons of this chastening.
⇒See the definition of reform in the KJV Dictionary
The Hebrew word is the same in a similar connection in Jer 6:8, where it is rendered, "Be thou instructed," and in Jer 31:18, "I was chastised." Ps 2:10 ("instructed"); Pr 29:19 ("corrected") use the Hebrew term of admonition by the words of man.
The King James Version also has "reform" in 2 Esdras 8:12; The Wisdom of Solomon 9:18.