You can check the status of page:

1. The status beside the title of the page
2. You can see if someone is already in charge of the change of the status
3. You can see where you are in the workflow

You can see the history of th workflow by clicking 

When a page is modified it comes back to the status 

And it has to be reapproved. 

The page that is visible by every body is the one that is 

But contributors can see that there is a version "in progress" and can switch from the version "in progress" to