You gain control of the targeted monster in the same Battle Position that it was in on your opponent’s side of the field. If it is face-down you may Flip Summon it and any Flip Effect is activated. During your End Phase it is returned to your opponent’s side of the field in the same Battle Position as you last had it in. So if you attacked with the monster and it remained in Attack Position, it will return to your opponent in Attack Position.
You can use the monster you control through the effect of “Change of Heart” as a Tribute for a Tribute Summon, or for an effect like “Cannon Soldier’s”.
Netrep Rulings:
“Change of Heart” is a targeting Spell Card.
It is not required to Flip the face-down monster taken control of by “Change of Heart” to look at it.
If the monster affected by “Change of Heart” is turned face-down, that monster will return to the original controller at the End Phase as normal.
If the monster affected by “Change of Heart” is temporarily removed from play, that monster will return to the original controller when the monster returns to play.
A face-up “Blindly Loyal Goblin” may not be targeted by “Change of Heart.” If a face-down “Blindly Loyal Goblin” changes control through the effect of “Change of Heart” or similar cards and “Blindly Loyal Goblin” is turned face-up, control of “Blindly Loyal Goblin” will not return to the original controller.
If a monster that changes control via “Change of Heart” is turned face-down by “Book of Moon,” the monster will return to the original controller’s field when the turn ends as normal per “Change of Heart.”
If a monster that changes control via “Change of Heart” is temporarily removed from the field via “Dimensionhole” or “Interdimensional Matter Transporter,” that monster will return to the original controller’s control when it returns to the field.
Netrep Q&As:
Q: If the opponent activates “Change of Heart” or “Snatch Steal” with only 3 Monster Zone spaces remaining and you chain with “Ojama Trio”, what will happen to the monster the opponent is trying to take control of?
A: When they take control of the monster, if there are no longer any open Monster Zone spaces for the taken monster it will be destroyed. Curtis Schultz, 01/28/2004
Q: Can “Change of Heart” or “Snatch Steal” be activated to destroy an opponent’s monster if all 5 Monster Zone spaces are full or does it only happen during the resolution of a chain?
A: It is during the resolution of a chain. If you do not have any empty zones in your Monster Zone you cannot activate “Change of Heart” or “Snatch Steal” to take control of an opponent’s monster. Curtis Schultz, 01/29/2004
Q: If I use “Change of Heart” on a face up monster and then my opponent chains “Book of Moon” to flip his monster face-down, does my “Change of Heart” lose its target or do I get the monster that is now in face-down Defense Position?
A: “Change of Heart” will take control of the monster as normal. “Change of Heart” can be used to take control of a face-up or face-down monster, so using “Book of Moon” doesn’t prevent “Change of Heart” from resolving, or the monster from returning at the end of the turn. Steve Okegawa, 02/11/2004
Q: Say Player A plays “Snatch Steal” on Player B’s “Jinzo”. Then Player B uses “Change of Heart” on “Jinzo” and then “Book of Moon”. What would happen to “Jinzo”?
A: During the End Phase “Jinzo” would return to the previous controller. Player A, based on your example. Curtis Schultz, 01/18/2004