Factory reset the device. This is the required handoff step before selling, gifting, or recycling the sensor.
Reset clears the local and account state. Factory reset clears saved network, device configuration, claim, and account-linking information before transfer.
The next owner pairs from scratch. After reset, the next owner can go through Bluetooth pairing, Wi-Fi setup, and claiming as a new device.
If you no longer have the device. Contact support from the account email and include the device or order details you still have.