from UDE's Judge Certification Program (YGO)
Q:
I activate Elemental Hero Prisma's effect to reveal XYZ-Dragon Cannon and send X-Head Cannon to the Graveyard. I then summon Y-Dragon Head and equip it to my Prisma, whose name is now X-Head Cannon. At the end of the turn would Y-Dragon Head be destroyed because Prisma's name is no longer X-Head Cannon?
A:
If you send "X-Head Cannon" to the Graveyard with the effect of "Elemental Hero Prisma" and later in the same turn you equip it with "Y-Dragon Head", when "Elemental Hero Prisma's" name returns to normal in the End Phase, the equipped "Y-Dragon Head" is destroyed because "Y-Dragon Head" can no longer be equipped to it.
http://entertainment.upperdeck.com/community/forums/thread/1561820.aspx
Q:
I activate Elemental Hero Prisma's effect to reveal XYZ-Dragon Cannon and send X-Head Cannon to the Graveyard. I then summon Y-Dragon Head and equip it to my Prisma, whose name is now X-Head Cannon. At the end of the turn would Y-Dragon Head be destroyed because Prisma's name is no longer X-Head Cannon?
A:
If you send "X-Head Cannon" to the Graveyard with the effect of "Elemental Hero Prisma" and later in the same turn you equip it with "Y-Dragon Head", when "Elemental Hero Prisma's" name returns to normal in the End Phase, the equipped "Y-Dragon Head" is destroyed because "Y-Dragon Head" can no longer be equipped to it.
http://entertainment.upperdeck.com/community/forums/thread/1561820.aspx