MTG Keyword Rules — Comprehensive Rules Glossary

A spell or ability may instruct players to exchange something (for example, life totals or control of two permanents) as part of its resolution. When such a spell or ability resolves, if the entire exchange can’t be completed, no part of the exchange occurs. Example: If a spell attempts to exchange control of two target creatures but one of those creatures is destroyed before the spell resolves, the spell does nothing to the other creature.

When control of two permanents is exchanged, if those permanents are controlled by different players, each of those players simultaneously gains control of the permanent that was controlled by the other player. If, on the other hand, those permanents are controlled by the same player, the exchange effect does nothing.

When life totals are exchanged, each player gains or loses the amount of life necessary to equal the other player’s previous life total. Replacement effects may modify these gains and losses, and triggered abilities may trigger on them. A player who can’t gain life can’t be given a higher life total this way, and a player who can’t lose life can’t be given a lower life total this way (see rules 119.7–8).

Some spells or abilities may instruct a player to exchange cards in one zone with cards in a different zone (for example, exiled cards and cards in a player’s hand). These spells and abilities work the same as other “exchange” spells and abilities, except they can exchange the cards only if all the cards are owned by the same player, and they can exchange the cards even if one zone is empty.

If a card in one zone is exchanged with a card in a different zone, and either of them is attached to an object, that card stops being attached to that object and the other card becomes attached to that object.

If a spell or ability instructs a player to simply exchange two zones, and one of the zones is empty, the cards in the zones are still exchanged.

A spell or ability may instruct a player to exchange two numerical values. In such an exchange, each value becomes equal to the previous value of the other. If either of those values is a life total, the affected player gains or loses the amount of life necessary to equal the other value. Replacement effects may modify this gain or loss, and triggered abilities may trigger on it. A player who can’t gain life can’t be given a higher life total this way, and a player who can’t lose life can’t be given a lower life total this way (see rules 119.7–8). If either of those values is a power or toughness, a continuous effect is created setting that power or toughness to the other value (see rule 613.4b). This rule does not apply to spells and abilities that switch a creature’s power and toughness.

One card (Exchange of Words) instructs a player to exchange the text boxes of two creatures. This creates a text-changing effect (see rule 612, “Text-Changing Effects”). In such an exchange, the rules text of each permanent becomes the previous rules text of the other.