It's possible to change Rotom forms in Pokémon Legends: Arceus. Trainers will need to purchase the appropriate appliance from the Glinko Shop.
After catching Rotom, players will get the Secret Key, which is needed to open the secret Rotom Room inside Eterna City's Galactic Building. Here, players can change Rotom's form by accessing the myriad of appliances available there. More: Pokémon: How To Receive Mystery Gifts In Brilliant ...