A more thorough explanation:

Rebus integris (ree-bəs in-tə-gris) is a Latin term used in Scots law. It means that matters are complete and no performance has taken place. For instance, if a contract has been signed but nothing has been done towards fulfilling it, the contract can be cancelled.

Suppose that a person signs a contract to buy a car from a dealer, but the dealer has not yet delivered the car or received payment. If the buyer changes their mind and wants to cancel the contract, they can do so because rebus integris applies. The contract has not been performed, and therefore, it can be rescinded.

Another example could be a contract for a service that has not yet been provided. If the service provider has not started working on the project, the contract can be cancelled because rebus integris applies.

These examples illustrate how rebus integris applies when no performance has taken place. If a contract has not been fulfilled, it can be cancelled or rescinded.