Turn off the headphones
Disconnect the headphones from any USB cable
Press and hold the Power button and the NC/AMB button together for about 7 seconds
Release the buttons when the indicator light flashes or the headphones reset
If that does not work, check the model-specific reset method in the user manual
For a factory reset, press and hold the Power button and the NC/AMB button for about 10 seconds until the indicator flashes differently
Re-pair the headphones with your device after resetting