Plug in your Echo Dot and wait for it to power on
Press and hold the Action button for about 25 seconds
Wait until the light ring turns orange, then blue, then back to orange
Release the button when the light ring indicates setup mode
Open the Alexa app and set up the Echo Dot again
If needed, use the reset method for your specific Echo Dot model
For Echo Dot with a microphone off and volume down button, press and hold the Microphone Off and Volume Down buttons for about 20 seconds