In conflict of laws, renvoi (from the French, meaning "send back" or "to return unopened") is a subset of the choice of law rules and it may be applied whenever a forum court is directed to consider the law of another state.

The procedure for conflict cases.

1. The court must first decide whether it has the jurisdiction to hear the case (which will involve addressing the question of whether the plaintiff is attempting to manipulate the judicial system by forum shopping).

2. Characterization. The court must analyze the case as pleaded and allocate each component to its appropriate legal classification, each of which will have one or more choice of law rules attached to it.

3. The court will then apply the choice of law rules. In a limited number of cases, usually involving Family Law issues, an incidental question may arise which will complicate this process.

In the Roman conflict of laws, an incidental question is a legal issue that arises in connection with the major cause of action in a lawsuit. The forum court will have already decided that it has jurisdiction to hear the case (resolving any issue relating to forum shopping) and will be working through the next two stages of the conflict process, namely: characterisation and choice of law. For example, the court may classify the cause as "succession", but it notes that the plaintiff brings the claim for relief as the deceased's widow. Before the court can adjudicate on the main issue, it must first decide whether the plaintiff actually has the status claimed, i.e. the incidental question would be the validity of the claimed marriage. The inconvenient reality is that many lawsuits involve a number of interdependent legal issues. In purely domestic cases, this poses no difficulty because a judge will freely move from one domestic law to another to resolve the dispute. But in a conflict case, the question is whether the incidental question is resolved by reference either to its own choice of law rules, or to the same law that governs the main issue (the lex causae). States have not formulated a consistent answer to this question.