Remove Matter Device from Another Voice Assistant Using Alexa
If your Alexa-connected Matter device is also set up with a non-Alexa voice assistant, use the Alexa app to remove the device from that system.
For Matter devices connected to Alexa and a non-Alexa smart home, remove the devices from the non-Alexa smart home using the Alexa app.
To remove a Matter device from a non-Alexa smart home:
-  Open the Alexa app 
.   -  Select Devices 
.   - Find the device that you want to manage in your Devices list and select it.
 -  Select Settings 
.   - Select Other Assistants and Apps.
 - Find the voice assistant that you want to remove in the list.
 -  Select the remove/delete icon 
.   - Confirm that you want to remove the other voice assistant by selecting Delete.