you switch off your, press the power buttton and the volume up button at the same time till it gets into recovery mode. You will see an android robot image. Got to wipe data factory reset using the volume keys. When you get to wipe data, press the power button and the phone will begin to flash itself. After wards it will boot normally and the pattern lock will be erased. Note that you lose all data during the flash process. Hope you are answered.