ALPHA-ONE Factory Reset
Factory reset won’t delete your google account history.
This Factory reset recommended when you forget lock pattern and passwords.
[Second method]
Reset the phone to factory default settings.
All data in the internal storage is erased include google account history.
1.From the home screen open 'Settings'
2.After that select 'Backup&Reset' and tap Factory data reset
3.Choose Reset phone and select Erase everything to begin hard reset operation