Mo. Rev. Stat. § 94.220: Board to perfect 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 board of aldermen shall have power to relevy and reassess any such tax or assessment in manner provided in sections 94.190 to 94.330.