How to convert a 240V AC outlet to 120V AC outlet

Hello all, I need to replace the 240V outlet with 120V outlet. Give the outlet comes with two types, one is four-hole and the other is three-hole. Here is my plan, can someone double-check whether my plan is correct? In the case of four-hole 240V receptacle with a four-wire circuit, 1> In receptacle side, connect white wire to neutral terminal(silver), black wire to hot terminal(brass), and connect green/bare wire to ground terminal(green). Finally wrap the red wire and do NOT use it. 2> In the power panel, replace the 240V 20amp breaker with 120V 15 amp breaker. Then connect white wire to neutral bar, black wire to hot bar, and green/bare wire to ground bar. Finally wrap the red wire and do NOT use it. In the case of three-hole 240V receptacle with a three-wire circuit