Modification & Discharge

Once a contract is in motion, the parties often want to change it. Modification doctrine asks when the law will enforce that change — and the answer turns on a single tension: certainty (hold parties to their promises) against flexibility (let parties adapt to circumstances they did not foresee). Today traces the doctrine’s evolution from a rigid common-law rule to the more forgiving standards of the Restatement and the UCC, with two cases that bookend the shift.

The pre-existing duty rule

R2d § 73. A promise to do what one is already legally bound to do is not consideration. At common law, a modification was itself a contract that needed fresh consideration; a party demanding more money for the same performance offered nothing new, so the modification failed. The rule’s purpose is to deter the “hold-up game” — a party with leverage refusing to perform unless the other side pays more. Many students still over-cite this hardline form, so note up front that it is no longer the majority rule.

The modern exception

R2d § 89. A promise modifying a duty under a contract not fully performed on either side is binding without new consideration if (1) the modification is fair and equitable in view of circumstances not anticipated when the contract was made, or (2) to the extent provided by statute, or (3) justice requires enforcement in view of material reliance. This shifts the inquiry from form (was there a fresh peppercorn?) to substance (was the change fair, voluntary, and prompted by genuinely unanticipated difficulty?). Coercion and duress are still policed — now under § 89’s fairness gate and the duress doctrine of R2d § 175 rather than through the consideration requirement.

Modification under the UCC

UCC § 2-209. For sales of goods, an agreement modifying the contract needs no consideration to be binding. The backstop is good faith: comment 2 makes a modification extorted “without legitimate commercial reason” ineffective, so the UCC catches the same hold-up the common law caught at the consideration stage — but at the good-faith stage instead. The section also allows enforceable no-oral-modification clauses, letting sophisticated parties lock in formality.

Cases

Alaska Packers’ Association v. Domenico (9th Cir. 1902): salmon fishermen who had signed on for a season demanded higher pay mid-season, on a remote Alaska shore where the cannery had no alternative labor. The cannery agreed in writing, then refused to pay. The modification was unenforceable for lack of consideration — the fishermen already owed the work — and the opinion frames the demand as an unjustifiable exploitation of the cannery’s necessity. This is the bright-line pre-existing duty rule at its most dramatic.

Angel v. Murray (R.I. 1974): a city refuse collector requested more money when the number of dwelling units jumped 400 in a year, far beyond the 20–25 the contract assumed. The city voluntarily agreed. Adopting R2d § 89, the court enforced the modification: it was made before completion, voluntary, and fair and equitable in light of genuinely unanticipated circumstances. Angel states the modern rule and disaffirms the rigid Alaska Packers approach.

What you should be able to do

Apply the pre-existing duty rule to a mid-performance demand and explain why the same-performance promise supplies no consideration; run R2d § 89’s fair-and-equitable test on an unanticipated-circumstances pattern; and apply UCC § 2-209’s good-faith standard to a goods modification, explaining how the UCC reaches the common law’s anti-hold-up result by a different doctrinal route. The capstone returns to the seam where a contract right is handed off to a stranger to the bargain.