Art. 1066 Action matured or acquired after pleading

If a defendant gets a new legal claim against the person suing them, or if their existing claim becomes valid, after they've already filed their answer to the lawsuit, they don't automatically lose the chance to bring it up. They can ask the court for permission to add this claim later through what's called a supplemental pleading.

This matters because normally you need to raise your claims against the other side early in the case. This rule gives some flexibility when circumstances change after the case has already started. For example, if a defendant later becomes entitled to sue the other party over something related to the case, or picks up a claim that didn't exist when they first responded, they can still bring it forward.

The key thing to remember is that this isn't automatic. The defendant has to ask the court for permission first. The judge decides whether to allow the new claim to be added to the case at that later point.