A party may perform his duty through a delegate unless otherwise agreed or unless the other party has a substantial interest in having his original promisor perform or control the acts required by the contract. No delegation of performance relieves the party delegating of any duty to perform or any liability for breach.
Except as otherwise provided in [UCC § 9-406], unless otherwise agreed, all rights of either seller or buyer can be assigned except where the assignment would materially change the duty of the other party, or increase materially the burden or risk imposed on him by his contract, or impair materially his chance of obtaining return performance. A right to damages for breach of the whole contract or a right arising out of the assignor's due performance of his entire obligation can be assigned despite agreement otherwise.
The creation, attachment, perfection, or enforcement of a security interest in the seller's interest under a contract is not a transfer that materially changes the duty of or increases materially the burden or risk imposed on the buyer or impairs materially the buyer's chance of obtaining return performance within the purview of subsection (2) unless, and then only to the extent that, enforcement actually results in a delegation of materialperformance of the seller. Even in that event, the creation, attachment, perfection, and enforcement of the security interest remain effective, but (i) the seller is liable to the buyer for damages caused by the delegation to the extent that the damages could not reasonably be prevented by the buyer, and (ii) a court having jurisdiction may grant other appropriate relief, including cancellation of the contract for sale or an injunction against enforcement of the security interest or consummation of the enforcement.
An assignment of "the contract" or of "all my rights under the contract" or an assignment in similar general terms is an assignment of rights and unless the language or the circumstances (as in an assignment for security) indicate the contrary, it is a delegation of performance of the duties of the assignor and its acceptance by the assignee constitutes a promise by him to perform those duties. This promise is enforceable by either the assignor or the other party to the original contract.