Air New Zealand allows travelers to upgrade their flight to a premium class cabin. Here, passengers with elite status in Airpoints or Star Alliance Gold may occasionally receive complimentary upgrades when seats are available. However, a free upgrade is not given to all flyers, but anyone can make an upgrade by paying for it. Further, by making an Upgrade on Air New Zealand, one can avail of benefits such as priority boarding, faster security check-in, special assistance during the journey, and so on. To avail more details related to the upgrade, contact the customer service of Air NZ or check out the blog linked above.