When a person intentionally interferes with your contract with another person, without justification, that causes you damages (e.g., loss of the contract), you have a claim against that third party for tortuously interfering with you and your contract counterparty.  In New York, the law does not impose the requirement that the third party interferer act with mal intent in procuring the breach of your contract.  The interferer simply must be aware that such a contract exists.  On the other hand, where a third party interferes with your prospective or existing economic relations, the law generally requires evidence that the interferer procured severance with your economic relations through wrongful means or with malicious intent.