To exchange a card is to return it to its pile (Supply or otherwise) and put another card in the discard pile in its place. The card returned is not considered trashed, and the card received is not considered gained. Most cards that exchange themselves are in the two Traveller sequences in Adventures: chains of cards of increasing cost and power, where each one may be exchanged for the next stronger one when discarded from play (though the top two cards in these chains, Champion and Teacher, are not Travellers themselves).
Aside from Travellers:
- Changeling (from Nocturne) can be exchanged into when gaining another card,
- Vampire and Bat (also from Nocturne) exchange into each other,
- Trader allows you to exchange any card you gain for Silver,
- Hermit can be exchanged for a Madman.
 Official Rules
 From Adventures
- When a player discards a Traveller from play, they may exchange it for the card indicated; they return the card being exchanged to its pile, take the card they are exchanging it for, and puts that card into their discard pile.
- For example when exchanging Peasant for Soldier, they put Peasant back into its pile and takes a Soldier and puts it into their discard pile.
- Exchanging is not trashing or gaining, and so does not trigger abilities like Travelling Fair's.
- It is optional.
- It only happens when the card is discarded from play; discarding it from hand, such as due to not playing it, will not trigger it.
- It only happens if the card being exchanged for has any copies available; if there are no Soldiers in the pile, Peasant cannot be exchanged at that time.
- If multiple cards do something when discarded from play, the player picks the order; for example, with no Soldiers left in the pile, a player with Peasant and Soldier in play could first exchange Soldier for Fugitive, then exchange Peasant for that Soldier.
 From Nocturne
- Nocturne has three cards that tell a player to "exchange" a card for another card. The card being exchanged is returned to its Supply pile, or non-Supply pile, and the card being exchanged for is taken and put into the player's discard pile. This does not count as gaining a card. The exchange only happens if both cards can be exchanged; if the pile is empty, the cards are not exchanged.
 Other rules clarifications
- Unlike gaining, exchanging can happen with a non-Supply pile without special instructions. For instance, you can use Trader to exchange a Horse for a Silver even though the Horse pile is not part oft the Supply.
- The card being returned as part of the exchange must have a pile to go back to. Therefore cards that don't have piles of their own anywhere, such as Shelters, Heirlooms, or Zombies, cannot be involved in an exchange.
- The Black Market deck is not considered a pile; so for example if a Traveller, Vampire, or Hermit is bought using Black Market, there is no pile to return it to and therefore it cannot be exchanged.