$cancelId = 5;//id for entry to update
    $cancel = $this->_cancelFactory->create();
    $cancel->load($cancelId);
    $cancel->setCancelStatus('Review');
    $cancel->save();

But as explained in the answers in here: http://magento.stackexchange.com/q/114929/146, `load` and `save` are deprecated. You should create service contracts for your module.