Aura swap

Aura swap is a keyword ability. It lets you switch an Aura that has it for an Aura in your hand. It was first introduced in Future Sight. By nature, this is a blue ability and it has only been printed on one Aura so far Arcanum Wings.

From the Comprehensive Rules

• 502.62. Aura swap
  • 502.62a Aura swap is an activated ability of some Aura cards. "Aura swap [cost]" means "[Cost]: You may exchange this permanent with an Aura card in your hand."
  • 502.62b If either half of the exchange can't be completed, the ability has no effect.

Example: You play the aura swap ability of an Aura. The only Aura in your hand can't enchant the permanent that's enchanted by the Aura with aura swap. The ability has no effect.

Example: You play the aura swap ability of an Aura that you control but you don't own. The ability has no effect.

• As the aura swap ability resolves, you may choose an Aura card in your hand. If you decide not to choose one (or don't have one), nothing happens. If you do choose one, the game checks whether that Aura can enchant the enchanted permanent as it currently exists (while the Aura with aura swap is still in play). If it can't, nothing happens. If it can, and the Aura with aura swap is still in play, and you own the Aura with aura swap, then the Aura with aura swap is put into your hand and the chosen Aura is put into play attached to that permanent.

• The exchange is simultaneous. At no time will the permanent be enchanted by both Auras or by neither Aura.

• If a non-Aura somehow gains aura swap, the ability will do nothing when it resolves. The Aura in your hand can't be put into play enchanting nothing, so the exchange doesn't happen.