To reset your X2, you will get the headset into pairing mode (green and red alternating lights).
Once in pairing mode press and hold both volume buttons for 3 seconds.
X2 light will indicate the headset is reset by flashing yellow three times. Your headphones are now reset.
If the headset is already turned on in Standby mode, or connected to an audio device, you can get the headset into pairing mode by pressing and holding both volume buttons until you see the light on the headset begin to flash red and green, indicating pairing mode.
Follow the steps above at this point to reset your X2 headset.