At any time, the Voice Dimmer can reset to it's factory default settings by pressing and holding both buttons (On and Off Buttons) together for 7 seconds (release when the Status Indicator starts flashing green).
Then, press and hold the ON Button for 7 seconds (release when the status light flashes red/amber).
Once the DWVAA is fully reset, you will hear Alexa say,
“Device is ready for setup. Follow the instruction in it’s companion app.”