Hello ZacharyZ,
If you have a Boot Camp on your Mac, you convert the Boot Camp to Parallels Virtual Machine ( kb.parallels.com/113658 )
You can start the Virtual Machine after importing from the Boot Camp and whatever Changes that you make to your VM will be reflected on your Boot Camp as well and it is not required to reboot your Mac.
However, it is not possible to convert a Virtual Machine ( created using a DVD or an image file ) to Boot Camp by any Parallels means.
Thanks,
Maheeshwar