The exact labels can vary between desktop and app experiences, but the flow is the same: start a replacement request, choose the reason that you want to change your card design, then select Mirror
The real trick comes from sacrificing something like Ichor Wellspring to draw a third card for a nasty Ancestral Recall impression
However, all isnt lost if you still want to use this mechanic
You can learn more about these in our full section on Dennys hologram baseball cards
But, like many Japanese versions (especially recent ones), it's fair to expect a close to 1:1 comparison between the twinned expansions
Then, on chapters two and three, it boosts your tribe by drawing you a card every time a merfolk (or kraken, leviathan, octopus, or serpent) attacks