The people of the City, by their approval of the Sales Tax ordinance, hereby authorize the City Council, by ordinance duly enacted, to make such administrative and technical changes or additions in the method and manner of administering and enforcing this chapter as may be necessary or proper for efficiency and fairness. Neither the rate of the tax herein provided nor the use to which the revenue is put shall be changed without approval of the qualified electors of the City as provided by law. (1988 Code § 7-225)