פירוש על עבודה זרה 71:10

As we learned above, R. Yehudah Hanasi (the grandson of the rabbi who edited the Mishnah) undid the decree on Gentile oil. But how could he do this? Surely, a later court cannot annul the decrees of the earlier court, and all the more so if the earlier decree was one of the 18 things that were decreed upon by Bet Hillel and Bet Shammai!