You are attempting to modify the active policy. You can only modify those policies that are not active.
To modify the currently active policy, you must first activate another policy. Activating the other policy will automatically deactivate this policy.
If you are using the SAN File System console, you can then create a new policy by cloning this policy.
If you are using the administrative command-line interface, you can then create the policy again, specify the force parameter to overwrite this policy.
Parent topic: Administrative messages