I understand how indulgences work an all. To my understanding, you can offer up an indulgence for yourself and also for others. Can someone elaborate what it means if I offer a plenary indulgence specifically for someone else? Is there criteria for the effects of the indulgence to 'work'? Does the person need to be receptive as he or she needs to be with grace?

Thanks.

Norms on Indulgences

[from the Enchiridion of Indulgences issued on 29 June 1968.]

1. An indulgence is the remission before God of the temporal punishment due for sins already forgiven as far as their guilt is concerned. This remission the faithful with the proper dispositions and under certain determined conditions acquire through the intervention of the Church which, as minister of the Redemption, authoritatively dispenses and applies the treasury of the satisfaction won by Christ and the Saints.

2. An indulgence is partial or plenary, according as it removes either part or all of the temporal punishment due for sin.

3. No one, acquiring indulgences, can apply them to other living persons.

4. Partial as well as plenary indulgences can always be applied to the departed by way of suffrage.

Full list of norms