Presidential Allowance Modernization Act of 2017 This bill amends the Former Presidents Act of 1958 to to revise provisions governing the compensation provided to a former President. Each former President shall receive from the United States: (1) an annuity of $200,000 per year; and (2) a monetary allowance of $500,000 per year for five years beginning six months after the expiration of his or her term, $350,000 per year for the next five years, and $250,000 per year thereafter. Such annuity and allowance shall be increased each year by the same percentage as Social Security benefits. Such allowance shall be reduced by the amount the former President's earned income exceeds $400,000. The bill: (1) limits the office staff provided for each former President to not more than 13 individuals, and (2) requires that suitable office space for a former President be provided on a reimbursable basis. The bill increases and provides for cost-of-living adjustments to the monetary allowance for surviving spouses of former Presidents.