The written agreement of a professional partnership stated that, during the first year of operations, no partner could draw more than $300 earnings per week, and that no partner could take a vacation. All members would have to rely on personal savings and credit if they needed more funds. The business prospered beyond expectations. After six months, four of the five partners agreed to increase the permitted draw to $500 a week, and three of the five voted to permit up to one week of vacation without pay. Are these modifications legal and binding?