Beulah Friedman (defendant) was sponsoring a plan to convert a residential apartment building into a building cooperative. Viola Sommer (plaintiff) was a tenant in the building. Tenants had the opportunity to own their apartment by purchasing securities in the building cooperative. In April of 1981, Friedman amended the plan to increase the price on the apartments. At the same time, Friedman included the following provision: “each tenant is granted the nonexclusive right to purchase his or her apartment at the [former] price . . . for a period of thirty (30) days.” However, Friedman revoked the offer prior to the expiration of the 30-day period – and prior to Sommer’s acceptance of the offer. Sommer then accepted Friedman’s offer within the 30-day period. Friedman refused to sell. Sommer sued Friedman, arguing that the April offer was irrevocable as a firm offer. Sommer was successful at the trial court and appellate level. Friedman appealed to the highest court in New York, the New York Court of Appeals.