Exchange

Exchange is a keyword action. One of the big things the Sixth Edition rules change did was to try to consolidate how Magic card text referred to things. The game had always had it, but it wasn't until then that exchange got its own vocabulary word.
==Description==
There are three major use cases for the action of "exchange", with a fourth obsolete use related to ante.
===Control===
The largest set of "exchangers" swap control between two permanents. Each must exist upon the battlefield during the resolution. There are two cards ( and ) that exchanges a card from the stack, which is the only other zone where a player has control of an object - the exile zone has ownership but not control. exchanges text boxes, but by itself the card is functionally close to an exchange of creatures plus a power/toughness setting effect.
 is a card that once had "exchange" in its rules text, but control changing effects meant the terminology needed to be spelt out. Aura Swap, a similar effect, has rules baggage preventing the effect if the controller of the aura swapper is not its owner. Finally, ante usage did not have this issue, as the changing of owners circumvented the "control can only change on the battlefield or stack" rule. As such, it could exchange objects from any zone, including the graveyard, hand and library.
===Objects in zones===
The second set of exchangers that swap all cards in two zones with each other - due to the nature of ownership and shared zones, this is limited to the hand, library and graveyard. One card of each exchange has been printed: (hand and library), (hand and graveyard) and (graveyard and library).
===Numerical===
Finally, there are a set of numerical value exchangers. Most commonly two life totals are exchanged, but a handful of cards exchange life total with power () or toughness ( and ). Any change in life total will trigger effects that track life gain or loss. This also results in some amount of memory issue with exchanging life with power or toughness, as these effects are permanent, and the creature will continue to exist with an altered stat.
Separately, there are three cards that exchange power or toughness. exchanges its power with a target creature it's blocking, while the Alchemy card allows for the exchange of base power and toughness. allows for it's base power or toughness to be exchanged with a dice roll.
==Rules==
==References==