Changing Filters for blocks on campaigns and newsletters

We have a blocked filter that was set up incorrectly, not afraid to admit that I'm a novice in marketo , we can't figure out how to change that block. Our smart list subscription is high, but over 60% is blocked due to a filter being placed that requires someone to be a part of a static list. Has anyone run into something similar? or have an idea how to get rid of this?