How to re-format hard drive?

Resolved. I changed to a USB 3 500GB hard drive, pushed the Blue Button one rapid tap. The system not only recognized the drive, like the others, but came up asking me to format it.

Just in case someone else is reading this, the blue button tap is a Tablo re-boot, not a system reset. All settings were remembered just fine, channels, WiFi, everything.

Thank you, I understand holidays and weekends.