If you want to change the capabilities assigned to any role, you can select different capabilities. You can also define additional roles and assign capabilities to them.
To add a role:
Click Admin on the main menu.
Click the Security option and then select Roles from the second drop-down list. The Roles window opens.
Click +Add role. The Add Role window opens.
Enter the name of the new role in the Name field.
Select the capabilities that you want to assign to the role. See Roles and Capabilities for more information.
Click OK. The new role appears in the Roles window.
Click Close on the Roles window.
This new role can now be used to define permission definitions for default,
base, user and group permissions.
To change a role:
Click Admin on the main menu.
Click the Security the options then select Roles from the second drop-down list. The Roles window opens.
Click the select icon 
at the end
of the appropriate row. The Change Role window opens.
Change the capabilities assigned to the role. See Roles and Capabilities for more information.
Click OK.
Click Close on the Roles window.
To delete a role:
Click Admin on the main menu.
Click the Security the options then select Roles from the second drop-down list. The Roles window opens.
Click the delete icon 
at the end
of the appropriate row. The role will be deleted.
Click Close on the Roles window.