Rule 805.3a

The process for handling mulligans is altered accordingly. First, each player on the starting team, in whatever order that team likes, declares whether that player will take a mulligan. Then the players on each other team in turn order do the same. Teammates may consult while making their decisions. Then all mulligans are taken at the same time. A player may take a mulligan even after a teammate has decided to keep their opening hand. After all players have kept an opening hand, any player on the starting team whose hand contains fewer cards than that player’s starting hand size may look at the top card of their library. That player’s teammates may also look at that card. The player may put that card on the bottom of their library. This process is repeated for each other team in turn order. See rule 103.4.

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