Passengers can make JAL airline upgrades via direct payment during the booking or after the reservation by visiting the official website of Japan Airlines or from the check-in counter at the airport. However, the Japan Airlines Upgrade to Business Class is given at the last minute, only when there is a seat available on the flight. Moreover, travelers can also request an upgrade using options such as using miles or bidding. For further insights on benefits and guidelines related to the upgrade, contact the customer service of Japan Airlines or follow the link to the blog.