Where a lease contains both an option clause requiring the lessee to 'give' notice and a separate mandatory service clause prescribing the method of service, non-compliance with the service clause does not invalidate the exercise of the option if notice was actually given; the consequence is a breach sounding in damages (being the lessor's costs of verifying service). A service clause using 'shall be served' (for notices on the lessor) as distinct from 'shall be sufficiently served' (for notices on the lessee) is mandatory rather than facultative. At common law, there cannot be personal service on a corporation aggregate, and delivery to a managing agent subsidiary does not constitute personal service on the lessor company.
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