It would probably be better to ask your advisor or someone at your school as each school will have different ways to go about it. Short answer would be to find a similar or equivalent class and take that, but make sure you get it approved before you sign up for it.
I need to re-take about 5 classes (including the one in question), but that's the only one that's no longer offered at my school. Since it's 1 credit I thought people might say maybe I should forget it and focus on the other ones.
Allopathic schools do not offer grade replacement so there is no point in retaking a class... any one credit class will balance out any other 1 credit class.