Nintendo has announced a change to the way it handles digital pre-purchases of games on the Nintendo eShop, undoing what was arguably a somewhat anti-consumer practice. Up until now, pre-purchasing digital titles ahead of their release meant that the customer would be charged immediately, and the purchase couldn't be cancelled. Essentially, rather than "pre-orders" per se, these were pre-purchases, so you owned the title as soon as you bought it, even if it was a long way from being available.
With the change, highlighted today on Nintendo's Japanese website, when customers place an order on a yet-unreleased title, the purchase won't be fully completed, and instead the game will just be reserved. Customers then have until up to seven days prior to the game's official release to cancel the preorder, so they're not charged for games they may not want anymore. Purchases become effective seven days before the game is released, and if you happen to preorder a game in that week leading up to release, then you'll still be charged immediately.
This change to Nintendo's policy is effective starting today, so past preorders aren't affected by it, but it should still be good news for customers going forward. You can manage you preorders from a dedicated section on the Nintendo eShop, under the user's profile settings.
A couple of years ago, Norwegian regulators reported a number of videogame companies, including Nintendo, for the way they handled cancellations of digital purchases, with Nintendo's case specifically regarding preorders. This change could be a way to alleviate these concerns.