code: public function updateInstance($process_id, $instance_id, $instance_update_item)
      {
          list($response) = $this->updateInstanceWithHttpInfo($process_id, $instance_id, $instance_update_item);
          return $response;
      }
docs: Operation updateInstance
  
  
  
  @param string $process_id ID of the process to retrieve (required)
  @param string $instance_id ID of the instance to retrieve (required)
  @param \ProcessMaker\PMIO\Model\InstanceUpdateItem $instance_update_item Instance object to edit (required)
  @return \ProcessMaker\PMIO\Model\InstanceItem
  @throws \ProcessMaker\PMIO\ApiException on non-2xx response