Hi Alison,
Just to note here...If the campaign is already launched. This does not remove them from the flow.
So let's say I had a campaign where the smart list was "First Name is Alison" and thus you qualified. If I ran that campaign today and the flow was:
1. Send Email
2. Wait 20 Days
3. Send Email
So you would have been sent the first email and now you are in the 20 day wait step.
Then tomorrow I go back to this same campaign and I change the smart list to "First Name is Michael"....just because you don't qualify anymore...this does not mean you are removed from the flow.
Maybe you understood that, just making sure ;).