1. Go to Phpmyadmin And Select Your Database.
2. Find table Name : “eav_attribute”
3. Then Find : “is_user_defined” field
4. There is_user_defined value each row containing to “0” –> This value is System Attribute value. You will change this value “0” to “1” now this is convert to normal attribute. Now this is not maintain “system_attribute_value” option.
5. once you change the value save and exit phpmyadmin.
6. Now you go to change your attribute in frontend, What you like.
And one more additional information. The magento not allowed to remove the “SKU“. Magento need to ask Compulsery in SKU.
So, you once you need to edit the Your own attributes set. You don’t need to Remove “SKU“. If you remove the “SKU“. The Magento Attributes not Save.