There are two ways to convert this 220-Volt branch circuit into a 110-Volt branch circuit. The first method requires removing the double-pole breaker and replacing it with two single-pole breakers as you did in steps one and two above.
When you convert 220- to 100-volt wiring, you have to cap off one of the hot wires and install a new, single-pole breaker to replace the double-pole breaker used for the 220-volt circuit. If you need to use a 220V receptacle for a 110V appliance, an easier solution is to use a 220 to 110 adapter.