I believe that once a clown changes to female it will not change back. They are all born male and the largest and dominant change to female (or clowns alone in an aquarium with no female to inhibit change).
So if you add 2 juvenile males to your tank at the same time the larger more dominant clown will become female. That situation will stay like that until the female is removed. If another clown is then added that is smaller than the male that you are left with the original male will turn into a female and the new smaller male will stay male.
So if you add 2 juvenile males to your tank at the same time the larger more dominant clown will become female. That situation will stay like that until the female is removed. If another clown is then added that is smaller than the male that you are left with the original male will turn into a female and the new smaller male will stay male.