Press and hold the Action button for about 25 seconds until the light ring turns orange, then blue, then orange again
Wait for the device to enter setup mode
Open the Alexa app
Go to Devices
Select Echo and Alexa
Select your Echo Dot
Tap Settings
Tap Factory Reset if available
If needed, use the physical reset method for your model
For Echo Dot with a microphone off button, press and hold the Action button until the light changes
For Echo Dot with clock or newer models, press and hold the Action button for 20 to 25 seconds
For first-generation Echo Dot, use the reset pinhole and press and hold with a paper clip for about 5 seconds
Set up the Echo Dot again in the Alexa app