No change in the rate of tax upon persons engaging in providing services taxable under this chapter shall apply to business activities occurring before the effective date of the change, and, except for a change in the tax rate authorized by RCW 35.21.870, no change in the rate of the tax may take effect sooner than 60 days following the enactment of the ordinance establishing the change. The clerk, or his or her designee, shall send to each registered taxpayer a copy of any ordinance changing the rate or tax upon taxable services promptly upon its enactment. [Ord. 569 § 3, 2018.]