RIOT PLEASE LET ME BIND ATTACK MOVE TO MB1 AGAIN

I was playing morgana urf and for some godforsaken reason i thought that "hey, im gonna be using morgana e on myself most of the time, so let me bind e to self cast!" Anyways, next game im lux mid in regular, when i realize that its still the self cast, so it doesnt do anything. So naturally, in the middle of a game, i think, "let me just reset! It'll work out fine!" So now im here with my bindings all messed up and i cant fix the one thing ive been playing with since ive started this game. PLEASE LET ME BIND LEFT CLICK