The Nanoleaf Essentials devices only have a factory reset mechanism. This resets all user pairing and network information. This is performed differently between bulbs and light strips. “Turn off/on” refers to physically powering on/off the device with a switch.
Turn off, wait for 3 seconds, turn back on for no more than 3 seconds. Repeat for a total of 5 power cycles. Bulb will flash red three times if successful.
Hold the power and brightness up (+) buttons on the controller for 5 seconds. Note that these buttons must be pressed simultaneously - pressing one and then the other after and holding will not work. This is by design so that it’s more difficult to accidentally trigger a reset. The strip will flash white three times if successful.