Hard Reset HUAWEI S31HW

First method:

1. Turn off the phone by holding the Power button.
2. Press and hold at the sime time Call + Power + Volume Up button.
3. Release held keys when you see an Android Recovery Mode.
4. Press Volume Down to choose "wipe data/factory reset", and then push the Power button to confirm.
5. Select "Yes--delete all user data". Use Volume Down button to scroll and Power key to select.
6. To restart the phone, select "reboot system now".
7. Success! The hard reset is done!

Second method:

1. If the device is off press the Power button to turn it back on.
2. Go to Settings and then to Privacy.
3. Tap Factory data reset. 
4. Choose Reset phone and select Erase everything.
5. Well done!

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.