a revocation before the offer, the offer lapses, even though a term is attached to it. An offer expires if an acceptance is not received by the offeror before the stated time period (if one is provided) or within a reasonable time period (if none is provided), as well as if the offeror receives a rejection or if either the offeror or the offeree die or enter insolvency before an acceptance is received by the offeror. Where a purported acceptance is received either after the expiry of the applicable time period or which substantially modifies the terms of the proposed contract, it instead constitutes a counter-offer. Consent in Québecois contract law may only be given by an individual with the legal capacity to bind themselves, and must be "free and enlightened". It may be vitiated by error, fear, or lesion (i.e. unconscionability). A person whose consent is vitiated has the right to apply for annulment of the contract; in the case of error occasioned by fraud, of fear or of lesion, he may, in addition to annulment, also claim damages or, where he prefers that the contract be maintained, apply for a reduction of his obligation equivalent to the damages he would be justified in claiming. Error vitiates the consent of the parties or of one of them where the error relates to the nature of the contract, to the object of the prestation or to any essential element that determined the consent; but inexcusable error may not constitute a defect of consent. Error induced by the other party's fraud or with the other party's knowledge vitiates a party's consent. Fear of serious injury to the person or property of one of the parties vitiates their consent if the fear is induced by violence or threats exerted or made by or known to the other party or induced by abuse of power or a threat thereof. Lesion results from the exploitation of one of the parties by the other, which creates a serious disproportion between the prestations of the parties; the fact that there is a serious disproportion creates a presumption of exploitation. In cases involving a minor or a protected person of full age, lesion may also result from an obligation that is considered to be excessive in view of the patrimonial situation of the person, the advantages he gains from the contract and the circumstances as a whole.