Contracts on behalf of a registered society may be made, varied, or discharged as follows:
(a) Any contract, which if made between private persons would be by law required to be in writing, and if made according to the English law to be under seal, may be made on behalf of the society in writing under the common seal of the society, and may in the same manner be varied or discharged;
(b) Any contract, which if made between private persons would be by law required to be in writing and signed by the persons to be charged therewith, may be made on behalf of the society in writing by any person acting, under the express or implied authority of the society, and may in the same manner be varied or discharged;
(c) Any contract under seal which, if made between private persons, might be varied or discharged by a writing not under seal, signed by any person interested therein, may be similarly varied or discharged on behalf of the society by a writing not under seal, signed by any person acting
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