Two named approaches
Pagat describes jack-of-diamonds and called-ace partner systems. Read the full procedure for the one your group selects, including its conditions and special cases.
Write a useful table note
Record the full reference URL and the system name. Ask each player to explain what the choice affects before beginning. A group should not discover halfway through a hand that it assumed two different procedures.
Tool scope
Our card comparison has no player roles and no reserved-card logic. The scorebook stores each person’s agreed final change. Neither tool determines a partnership or applies its settlement automatically.