Windows 10 can't be removed in Boot Camp Assistant? macOS Sierra (10.12.2) - 2015 rMBP

Installed Windows 10 via a direct Windows' ISO using Boot Camp Assistant. Made a partition, it installed fine, worked fine and then it got messed up and needs to be re-installed. Problem is, Boot Camp Assistant doesn't show the Windows 10 partition. Starting up BCA, there is no 'install/remove Windows' option, or any other options to select except to continue to the next screen, which once again doesn't show the Windows partition, but just the full size of my Mac's SSD. It says it'll restore my MBP to it's original 490~ GB. Is this going to erase everything on it?

How can I remove this Windows 10 partition if Boot Camp Assistant doesn't recognize it? I'd use Disk Utility but then I'll be left with a phantom Windows boot loader and I don't need that. Is there any way to refresh/reinstall Windows 10 on that partition using the ISO I have?
you are going to half to  reformat though disk utility to fat32  and use usb drive your created with bootcamp to instal windows on that same drive again