XXXVI. On the heretical opinions that they shall be purged.
If a bishop, or a presbyter of some bishop or a deacon stumbles into heretical views, and for this reason is excommunicated, no bishop shall receive him in communion unless the excommunicated first having presented the written confession of faith (libellus fidei) gives satisfaction to everyone at the general council, and in such way shall be freely cleansed. This is also decreed for the lay faithful if they are accused of any heretical belief.
(trans. M. Szada)