That is just one translation. The word in Hebrew is וַיִּנָּ֣חֶם way·yin·nā·ḥem comfort self, ease one’s self, repent, A primitive root; properly, to sigh, i.e. Breathe strongly; by implication, to be sorry, i.e. (in a favorable sense) to pity, console or (reflexively) rue; or (unfavorably) to avenge (oneself) – comfort (self), ease (one’s self), repent(-er,-ing, self).
Another translation says “God was appeased” So because of Moses’ appeal, God did not destroy the Israelites, so you can say that he was appeased or “repented” or appeared to change his decision.