I typically use change program member status. I have tried using this flow step to move people out of success but keep them within the program but realized that didn't work. How does marketo know which status to put them in?
So...you can't go backward (usually) in Status. A Success point would usually mean they did something. If you need to correct a Status, you can kick out the leads and then put them back in at the correct Status. You can also push up to a Status that is not a Success.
Please look at the docs on Program Channel Status Setup in Admin > Tags > Channel