After you get the national pokedex go in the old chateau at eterna forest and go to the TV in there at nighttime.
Eterna Forest:you need cut.You can find rotom in TV.Also manapy!
you have to trade from pearl
it tells you how
rotom isn't in Pokemon emerald
solacoen ruins
in a Nintendo event
you have to get it at an event or get an action replay
Their is NO rotom in Pokemon ranger shadows of almia.
BY HAPPYNESS IN DAY IF IT is umbroen is in night
Heat Rotom: T8A6EH7Wash Rotom: H8S3A5WFrost Rotom: 6TS8ORF Fan Rotom: 9N4A4F8Mow Rotom: 7W6O3M5
Rotom is an Electric/Ghost-type Pokemon that is #479 in the National Pokedex. It has the ability to change in multiple forms - Heat Rotom, Wash Rotom, Frost Rotom, Fan Rotom, and Mow Rotom - that all have different secondary typing in addition to Electric.
Sorry, changing rotom is only in allowed in Pokemon Platinum. In diamond he has to stay boring old rotom.