Oppenheimer & Co., Inc. v. Oppenheim, Appel, Dixon & Co.

Oppenheimer's sublease agreement with OAD expressly required Oppenheimer to obtain and deliver the landlord's written consent to proposed construction by a set deadline or the agreement would be void; Oppenheimer's attorney only telephoned notice of consent on the deadline rather than delivering the writing itself, and OAD declared the agreement void, while Oppenheimer argued substantial performance and estoppel, and Olympia's separate rent-guarantee arrangement meant Oppenheimer suffered no actual damages from the deal falling through.