In theory, several agreements could be simultaneous, so it is not clear that they replace the other: (a) if different representatives of the same entity simultaneously negotiate an agreement on the same issue. For example, a real estate agency could accidentally sell the same home at the same time to different buyers. (b) when a contract is signed, the parties enter into other (oral) agreements or sign several related contracts at the same time. In summary, the parties should ensure that they are informed in advance of what was included prior to its execution and that it has been excluded from the contract. As we have seen, it is often necessary to include additional clauses in the contract in order to exclude unspoken clauses or pre-contract assurances or to include certain pre-contract agreements.