You can change the SAP system to modifiable or not modifiable via transaction code SE06 , you should be careful to change this option especially on SAP Production system.
Go to tcode –> SE06
Click the “System Change Option” button
Click the button “F5 – Display / Change” to enable modification for the settings.
You will get to the “system change option” configuration screen , you can change the system via EDIT menu selections to MODIFIABLE or NOT MODIFIABLE status
If you going to choose “System Modifiable” then you will see ;
If you going to choose “System Not Modifiable” then you will see ;
After you done the selection don’t forget to SAVE button before you going to leave…