Delete or update billing plan API

[Roman4852]

Hello. Sorry for my low English. I need to update or delete billing plan. I use the API $plan-> delete(). But nothing happens and the plan is again active. What I do wrong?

public function delete($apiContext = null, $restCall = null)
{
    ArgumentValidator::validate($this->getId(), "Id");
    $patchRequest = new PatchRequest();
    $patch = new Patch();
    $value = new PayPalModel('{
        "state":"DELETED"
    }');
    $patch->setOp('replace')
        ->setPath('/')
        ->setValue($value);
    $patchRequest->addPatch($patch);
    return $this->update($patchRequest, $apiContext, $restCall);
}