Regarding the mechanisms for changing halakhic law

Shalom Aleichem
I read in the book ‘Standing Among the Walking’ about mechanisms of change in Halacha.
The book cited many early sources that present various mechanisms, mainly those that support the claim that “a null and void reason invalidates a regulation,” but I did not see any reference to authoritative scholastic sources on the subject.
In Babylon we have the discussions on ‘a matter that is in one minyan, another minyan must permit it’ and there are no explicit discussions beyond that, but there are several sources in Yerushalmi (cited by many rishonim in halakhic law) in which it is explicit that even if a matter is nullified, a decree is not nullified (Yerushalmi Shabbat 6b, Ketubot 15, Terumot 115, Shabbat 2a, and also in Sheveit 4b and Sanhedrin 35, except that in the issue in these two sources there is an omission and the issues are treated by the text).
If so, how can permits based on ‘void of reason, void of regulation’ be used if this contradicts explicit authoritative scholastic sources?