Is it possible to change rotom's form in HeartGold?

Question

Or do I have to trade a different form from Platinum?

Answer 1

If you take Rotom to Silph Co. and have it at the front of you team, go to the Elevator and you'll be able to go up to it. Once there, Rotom will power up the elevator and take you to the room. In the room, select the respective item for Rotom's forms. You can change forms at will. To change Rotom out of that form and back to its base form, just select the tile where Rotom used to be.

So yes :D

Hope I helped! :) Source

Answer 2

If you take Rotom to Silph Co. and have it at the front of you team, go to the Elevator and you'll be able to go up to it. Once there, Rotom will power up the elevator and take you to the room. In the room, select the respective item for Rotom's forms. You can change forms at will. To change Rotom out of that form and back to its base form, just select the tile where Rotom used to be
^ Serebii

http://www.serebii.net/heartgoldsoulsilver/forms.shtml

Answer 3

Yes, you can change Rotom's form.

>If you take Rotom to Silph Co. and have it at the front of you team, go to the Elevator and you'll be able to go up to it. Once there, Rotom will power up the elevator and take you to the room. In the room, select the respective item for Rotom's forms. You can change forms at will. To change Rotom out of that form and back to its base form, just select the tile where Rotom used to be.

http://www.serebii.net/heartgoldsoulsilver/forms.shtml

---

The room should look like this.

Answer 4

Head to the Silph Co., with Rotom at the front of your party (out of it's Pokeball). Enter the Silph Co. and you will find the place is deserted.

Go into the elevator, and you'll arrive at a mysterious room with appliance that match Rotom's alternate forms. Click on one of the appliance for Rotom's form to change. Then, voila! Your new formed Rotom. You can come back anytime to change it's form.

Hope I helped. :)
Source