If we want to unpair to a Bluetooth device, for example because we no longer use it, we can do this in the Bluetooth settings; unpairing a device will delete the connection and would have to be restored when using it again with the Xiaomi smartphone.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Bluetooth
Step 3:  Open the  devices settings
Step 4:  Tap on  Unpair
  1. Open the Settings
  2. Tap on Bluetooth
  3. Open the devices settings
  4. Tap on Unpair

Xiaomi Instructions