In plain English, the case was closed, but now there is new evidence and we're investigating it. Sounds like 're-opening' to me.
The real news story here is that this is what everyone will be talking about for the next weekend, that's three days, with a response by her on Monday. So, maybe four days. That's more than 30% of the remaining election cycle.
As Trump would say. This is big league.
Why are we now shoehorning the real world in to TV speak?
https://www.washingtonpost.com/politics/fbi-to-conduct-new-i...
Perhaps it would have been better to admit fault and deal with this outright in the beginning, rather than attempting to manipulate the process[0].
[0]http://observer.com/2016/07/exclusive-security-source-detail...