LG L55C User Manual page 258

Note
Disconnections are manually done but often occur automatically if the
paired device goes out of range of your LG L55C or if it is powered off.
To delete a paired device (unpair):
Deleting a device from your list removes its "connection record"
and upon reconnection would require that you re-enter all the
previous pairing information.
1. Verify your Bluetooth is active.
2. From the Bluetooth settings page, touch and hold the name of
the previously paired device (under the Bluetooth devices
section). This opens the connected device's menu options.
3. Tap Disconnect & Unpair to confirm deletion.
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