You’ll find the Move Deleter in a house to the south of Canalave City’s Pokémon Center. You can use his services at any point after you acquire HM03 Surf.
The Move Deleter is an NPC who will force your Pokémon to forget any moves you no longer want them to know. Most notably, he’s the only character in the game who can delete Hidden Moves.
Finding the Move Deleter
The Move Deleter can be found in his house in Canalave City, which you’ll have access to as soon as you’ve obtained HM03 Surf from the elder of Celestic Town.
Locating the Move Deleter is simple.
Start by heading south from Canalave City’s Pokémon Center.
Then enter the house directly below the Pokémon Center and above the Poké Mart—this is the Move Deleter’s house.
The elderly Move Deleter will be standing at his table inside.
How To Make Pokémon Forget Moves
As his name implies, the Move Deleter can make your Pokémon forget any of the moves in their current moveset.
He is also the only person who can make your Pokémon forget HMs (Hidden Moves), which are otherwise irremovable (this feature is designed into Platinum to keep you from stranding yourself in areas that require Hidden Moves to leave).
The Move Deleter offers his helpful service at no cost—all you have to do is speak with him when you have the Pokémon you want to edit in your party.
Select “Yes” when he asks if you want him to force a move from your Pokémon’s repertoire, and he will have you choose a Pokémon from your party.
Once you’ve chosen a Pokémon, its move list will be displayed on the screen.
Select the move you would like to delete.
The Move Deleter will confirm if a move deletion is successful.
Note: The Move Deleter will not make a Pokémon forget a move if it’s the only move the Pokémon knows.
Your Pokémon will now have a blank spot where the move used to be.
The removal of Hidden Moves is typically the only reason to use the Move Deleter’s service. This is because regular moves can simply be overridden when teaching the Pokémon a new move via TM or via level-up.
But if a regular move gets deleted by accident, the Move Reminder in Pastoria City can help your Pokémon relearn it.