Mo. Rev. Stat. § 94.040: Council may correct illegal levy.

In case the corporate authorities of the city have attempted to levy any tax or assessment for improvements, or for the payment of interest or coupons on bonds issued and outstanding, or other evidences of debt, which tax or assessment may be informal, illegal or void in consequence of a failure to comply with the requirements of law, the council shall have power to relevy and reassess any such tax or assessment, in manner provided in sections 94.010 to 94.180.