You can't change Giratina's form in Pokemon Pearl (that includes Diamond).
You can change Giratina's form in Pokemon Platinum (that includes Heart Gold and Soul Silver).
You can change Giratina's form with the Griseous Orb.
To change Giratina's form give Griseous Orb to Giratina and then take it off and Giratina changed its form.
You cannot change his from in Pearl only Platinum.
you can't you can only change it in platinum
you can't
no not at all
Veilstone City.
You cant do it in pearl wihout a cheat. You can use The Gracidea Flower to transform it to Sky Form in Platinum though.
You change his form in pokemon diamond pearl and platnium, you need a special key though for something in eterna city
You do not go anywhere in "Pearl" to change Rotom's forms because you can't change its forms in "Diamond" or "Pearl." Rotom is only capable of changing forms in Platinum, HeartGold, SoulSilver, Black or White.
Go to Veilstone City and interact with 1 of the meteorites there, that'll change Deoxys' form into Attack, Defense, Speed or Normal Forme.
In Veilstone City. The south-east of Veilstone city.
They power up certain moves and change Arceus's type/form!
No, it never evolves, but you can change it's form on Pokemon diamond/pearl.