Historical Rules · 1 May 2012
Rule 805.3a
Official source text from the 1 May 2012 Rules release
The process for handling mulligans is altered accordingly. First, each player on the starting team, in whatever order that team likes, declares whether or not he or she 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 his or her teammate has decided to keep his or her opening hand. See rule 103.4.