If I taught a Pokémon a move tutor move, like Gunk Shot, and then replaced it with another move, could I get a Move Reminder to remind my Pokémon how to use the move tutor move again? Or would I have to get the move tutor to teach the move again?
From Generation II to VI, the Move Reminder can teach a Pokémon any move that its species is able to learn at an earlier level. In Generation VII, the Move Reminder can teach a Pokémon any move it can learn via level-up, including moves it would learn at higher levels. From Generation VI onward, any Pokémon hatched in Generation VI onward may also be taught any move it knew when it hatched; this includes Egg Moves, level-up moves bred onto a Pokémon, and Volt Tackle bred onto Pichu. Also in these games, Pokémon obtained via Mystery Gift can learn any specifically flagged move it knew when it was obtained; older events only flag event-exclusive moves (such as the Pokémon Center Tokyo Bay Inkay's Happy Hour) and Egg Moves, whereas more recent distributions flag all moves the Pokémon knows when obtained except moves that do not exist in Pokémon X and Y. Also, a special move known due to being a hidden Pokémon in Pokémon Omega Ruby and Alpha Sapphire or an Island Scan Pokémon in Pokémon Sun and Moon can also be taught by the Move Reminder if forgotten. The Move Reminder can only teach a Pokémon moves that its species can learn; they cannot teach moves exclusive to a pre-evolution. In particular, many Pokémon that evolve by evolutionary stone have a very restricted set of level-up moves in their evolved forms compared to their unevolved forms. For example, Eevee can learn Take Down by leveling up, but none of its evolutions can; this means that an Eevee could be taught Take Down by a Move Reminder (if it has the appropriate level prior to Generation VII), but a Vaporeon or other Eeveelution could not. Certain Pokémon may also be taught moves via the Move Reminder that they would not normally learn until a later level or at all by leveling up. For example, while Lopunny could normally only learn Healing Wish at level 63 by leveling up, a Move Reminder can teach the move to Lopunny before then since it also counts as one of Lopunny's starting moves. The move Rototiller can also be taught to Lopunny by a Move Reminder, and this is the only way for Lopunny to learn this move. Other moves can only be taught this way for reasons such as the Pokémon not being able to be obtained at a low enough level (e.g., Zapdos and AncientPower starting in Generation IV) or the species having more than four starting moves (e.g., Kecleon).
There's nothing in there about tutored moves. source
