Can.1596 $1. An interested party can be admitted to intervene in a case at any stage of the suit, either as a party defending ones own right or as an accessory to help a
given litigant.
$2. However, in order to be admitted, such an interested party before the conclusion of the case must present to the judge a libellus briefly demonstrating the right to
intervene.
$3. The person who intervenes in a case must be admitted at that stage which the case has reached with a brief and peremptory period of time assigned to present proofs if the
case has reached the probatory stage.
Can.1597 After hearing the parties, the judge must summon to the trial a third party whose intervention seems necessary.