The heirs at law of every deceased partner shall fulfill the agreement of their ancestor so devoting land to division and sale, by joining with the surviving partner or partners, or with the trustee or trustees, if any, holding the title, or with both the survivors and trustees, as may be necessary, in executing, acknowledging and delivering all deeds of conveyance necessary to convey to the purchasers of such lots, blocks or shares the parcels so purchased by them respectively, whether the agreement with such purchasers to sell the same were made by the copartnership during the lifetime of the said ancestor, or by the surviving partner or partners after his or her death, and whether the same were made before or since the taking effect of this act.