1. You can Disable & Enable a User Role using Lock User Role option in its tools area
If a User Role has assigned Users you will see an alert
2. Confirm your decision to Lock
3. See Locked User Roles under the Disabled tab
To Enable a User Role use Unlock User Role option in its tools area
You can not disable Default Roles.
If you are not an administrator, you will need to have permission to Disable & Enable a User Role. This will depend on a User Role assigned to you by your Administrator.