311. When there are several executors or administrators, the powers of all may, in the absence of any direction to the contrary, be exercised by any one of them who has proved the will or taken out administration. Illustrations (i) One of several executors has power to release a debt due to the deceased. (ii) One has power to surrender a lease. (iii) One has power to sell the property of the deceased whether moveable or immoveable. (iv) One has power to assent to a legacy. (v) One has power to endorse a promissory note payable to the deceased. (vi) The will appoints A, B, C and D to be executors, and directs that two of them shall be a quorum. No act can be done by a single executor.