The Ability Patch is a unique item in Pokémon Brilliant Diamond & Shining Pearl that all players should know how to get. The Ability Patch is only obtainable in-game after trainers beat the main storyline and unlock the additional content. It's an extremely rare item that unlocks the Hidden Ability of any Pokémon, but it can only be used once. Luckily, players can grab multiple Ability Patches in Pokémon Brilliant Diamond and Shining Pearl, but there is a large cost associated with grabbing the item.
Hidden Abilities aren't necessarily hidden from the game, but rather abilities that are only obtained on Pokémon through special means. For example, the Flame Body Ability in Pokémon BDSP is the common ability for Magby, but it's the Hidden Ability for Ponyta. The Ability Patch is one way of unlocking a Pokémon's Hidden Ability, and in-person events for past Pokémon games have distributed certain Pokémon with their Hidden Abilities already unlocked. Hidden Abilities can also be unlocked for Pokémon that can be found through the Poké Radar, and a Hidden Ability can be passed down to offspring through breeding. Once a Hidden Ability is unlocked for a Pokémon it can't be reversed, even by using another Ability Patch.
To clarify, the Ability Patch is a single-use item similar to an evolution stone and not a held item. Additionally, it will only unlock a Pokémon's Hidden Ability, and not change it to another common ability if a Pokémon has another one available. For example, Togepi can be found in Pokémon BDSP with one of two common abilities for its line, Hustle and Serene Grace. Hustle increases a Pokémon's physical Attack moves by 50% at the cost of 20% reduced accuracy, and when a Pokémon with the Hustle ability leads the party trainers are 50% more likely to find a Pokémon at a higher level. Serene Grace doubles the likelihood of added effects of offensive moves happening. For example, Togekiss' Air Slash normally has a 30% chance of making a target flinch, but if it has Serene Grace that chance increases to 60%. An Ability Patch wouldn't change a Togekiss' ability from Hustle to Serene Grace, or vice versa, but rather it would change both of the aforementioned to its Hidden Ability, Super Luck. Super Luck raises Togekiss' critical hit likelihood by one stage permanently.
Pokémon BDSP: How To Get An Ability Patch
The Ability Patch is a new item that was first introduced in Pokémon Sword & Shield Crown Tundra DLC. In Pokémon BDSP, the Ability Patch is only available for purchase in the Battle Park's exchange counter for 200 BP. Trainers will have to battle their way through the Battle Tower and earn enough BP to purchase a new Ability Patch every time they wish to use one.
After purchasing an Ability Patch, select the item from the bag and choose the Pokémon to use it on. Pokémon Brilliant Diamond and Shining Pearl will ask the player to confirm that they want to use the Ability Patch. Select "Yes", and the chosen Pokémon will now have its Hidden Ability unlocked, replacing the old ability.
Pokémon Brilliant Diamond and Shining Pearl are available for Nintendo Switch.