How can I let Author’s edit articles that have already been published?

I have about 30 different writers that write for our blog and they are all set to the “Author” user level. I use the Role Manager plugin to control the tasks they can do more precisely.

Right now Authors can’t “publish” articles…they can just submit them for review. But what I’d like to be able to do is after I’ve published their articles, let them edit their article. Right now, if they edit their article, it takes it off the site and puts it back in “pending review”.

Any ideas how to get around that?