This is a follow up to If a party says something about interpretation of contract, is it binding?

If the parties agree to a material change in a contract, but for whatever reason sign the original document, does the change the agreed to still apply?

For example someone is asked to sign a NDA. The NDA is very broad saying "never talk about anything you learn while in this position". If the person asks "can I talk about things that I learned after they become public knowledge" and they receive the answer"yes" but this all happens in a separate communication (e.g. a chain of emails). Would signing the original agreement invalidate the public knowledge part? What if the contract has some sort of integration/merger clause?

Another example is Bob is offered a job and asked to sign a boilerplate employee contract. The contract states that payable hours are only those done in the workplace. Bob asks his manager if he can be compensate for travel time and the manager says yes. If Bob signs the original boilerplate employee contract, does he wave his right to get paid for travel time?

I ask because I know sometimes administratively it may be difficult to change a contract. For example if it's boiler plate or if it's done online and requires replaces a file on a server etc. Is it sufficient just to have written communication even if it's prior to the signing?

This is different than the linked to question at the top, because that asks about clarifying an interpretation, but here I'm wondering about a more substantial change to a contract.

UPDATE: thanks to all who answered. I cannot pick a single correct one...

  • Your specific example may not be a good one. AFAIK you cannot NDA stuff that has already gone public. The purpose of an NDA is to prevent information to become public because it would cause damage. Once the information is public (by other means) saying it does not create any more damage and the NDA doesn't really do anything about it. Obviously this assumes you do not add any new bit of information... – Giacomo Alzetta Jul 26 at 9:17


No. The signed document supersedes any prior agreement. See the case law citation (specifically the excerpt that "The court generally may not consider extrinsic evidence of any prior agreement or contemporaneous oral agreement to vary or contradict the clear and unambiguous terms of a written, integrated contract") given in this comment.


That is the drafter's excuse for potentially disavowing at a later time whatever concession was agreed upon "on the side". For practical purposes, the protocol or administrative "difficulties" can usually be overcome by establishing the sought change(s) and making explicit reference(s) to the contract on which the change(s) would apply.

A court will not care why the prior or extrinsic agreement was not duly memorialized/incorporated in the contract. In the event of dispute, what matters is what the language of the contract provides.

  • 1
    Worth pointing out that an agreement after the contract was signed may supersede it (though good luck proving it if it's not in writing). – Tim Lymington Jul 25 at 21:39
  • @TimLymington That's correct. The latest meeting of the minds that can be proved constitutes [henceforth] the cognizable contract between the parties. If a party denies the existence of a superseding agreement which was not in writing, the parties' subsequent conduct might prove the existence of that superseding agreement. However, subsequent conduct must effectively prove that there was a superseding agreement so as to distinguish it from mere or temporary leniency on a party's breach of the original contract. – Iñaki Viggers Jul 26 at 10:41
  • So in summary if something clarifies the interpretation of a contract, it will be binding, but if something contradicts part of the contract, it will not be binding after the contract is signed? – justasking111 Jul 27 at 9:20
  • @justasking111 Interpretation and binding are two different things. Only the latest cognizable contract is binding. An interpretation does not change what is binding in a contract and what is not. But yes, if X contradicts part of a subsequent contract, X will no longer be binding because it is superseded by the subsequently signed contract. – Iñaki Viggers Jul 27 at 11:54

The proper way to handle this is to either 1) change the original contract to conform to the revised agreement before it is signed, which may be awkward, or 2) to create a separate, subsequent agreement, which explicitly says that it modifies the original. For maximum clarity, the separate agreement should be in writing, and have an explict date (possibly including a time) which clearly shows that it was executed after the primary agreement. Such a separate, subsequent agreement will normally be legally effective and binding on all parties.

As the answer by Iñaki Viggers says, an oral agreement at the time of the primary written contract, or a previous agreement to modify the contract, whether oral or in writing, will not generally be legally binding if there is a later dispute. But a later modification agreement can be done at any time after the main contract if all parties are willing.


The Parol Evidence Rule

The rule prevents parties who have reduced their agreement to a final written document from later introducing other evidence, such as the content of oral discussions from earlier in the negotiation process, as evidence of a different intent as to the terms of the contract.

To the extent that the document is a partial or complete integration of the agreement, if it says something then that is what the terms of the contract are with respect to that thing.

Unless there's an exception to the rule ...


These vary by jurisdiction. Some are extremly strict with the rule and allow almost no exceptions adopting an "if you wrote it, you meant it" methodology. Others are more liberal, adopting a "lets' find out what you really meant" methodology.

Typical exceptions include:

  • that the contract is partly oral and partly written,
  • there is a collateral contract,
  • there is an estoppel,
  • rectification of an error in the document,
  • conditions precedent,
  • implied terms,
  • consumer law or other legal requirements,
  • industry practice,
  • prior dealings.

Multiple documents

There is no requirement in contract law for a written contract to be a single document, indeed, in complex contracts the documentation may run to many volumes of contract terms, standards, plans, specifications etc. all of which are collectively 'the contract'.

For your examples, if you signed the contract and sent it via email with the issues you agreed detailed in that email then there is a very strong argument that the email and the signed contract together are the final agreement.

The specific examples

The specific exemption that you mention (information that is public knowledge) are excluded from the scope of an NDA by normal operation of law.

Bob would not be entitled to be paid for travel time unless that was a legal requirement outside the contract. For example, in most jurisdictions, employees are "on the clock" when travelling between worksites during the course of a shift by law and a contract can't take that entitlement away.

A written agreement 'prior' to the signing would fall foul of the parol evidence rule. A written agreement made 'contemporaneously' with the signing would itself be part of the agreement.

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