realign

: to make new divisions or groupings of; especially : to regroup (one or more litigants) to reflect the true arrangement of interests in a suit : to regroup (one or more litigants) to reflect the true arrangement of interests in a suit

Note: After examining the ultimate interests of the parties involved in a suit, the court might choose to realign the plaintiffs and defendants so that, for example, one of the defendants becomes a plaintiff.