Cortana Switcher can quickly enable or disable Cortana on the fly in Windows 10 Anniversary Update (Redstone 1).
Cortana Switcher accomplishes this by editing the registry and requires Administrator privileges. While you can run it form the ZIP, it will appear to be working but won't work unless you extract and Run as administrator.
It's a small, simple program that has two choices; enable or disable. You are prompted to reboot when you make the change.
That's it. If you need to turn Cortana on or off frequently, or just want to accomplish it quickly, then Cortana Switcher will get it done for you.