You have two options. You can reset your phone back to it's default settings like when you first got it OR you can reset and also erase everything else you've put in it including contacts, images and messages.
To reset phone
All saved contents and preference setting will be reset to factory defaults.
1. Press the Left Soft Key Menu > Settings > Security > Enter your password. > Reset Phone. (Note: The default Lock code is the last 4 digits of your phone number.)
2. “Reset phone?” will be displayed. Select “1. Yes” and press the OK Key.
3. “Really?” will be displayed. Select “1. Yes” and press the OK Key.
To erase all entries
All saved contents and preference settings will be reset to factory defaults.
1. Press the Left Soft Key Menu > Settings > Security > Enter your password. > Erase All Entries. (Note: The default Lock code is the last 4 digits of your phone number.
2. “Erase All Entries?” will be displayed. Select “1. Yes“ and press the OK Key.
3. “Really?” will be displayed. Select “1. Yes” and press the OK Key.