The fact that the contract has been let or that the improvement has been made and completed in whole or in part shall not prevent the reassessment from being made, nor shall the omission or neglect of any office or officers to comply with the law, the charter, or ordinances governing the city or town as to petition, notice, resolution to improve, estimate, survey, diagram, manner of letting contract, or execution of work or any other matter connected with the improvement and the first assessment thereof operate to invalidate or in any way affect the making of a reassessment.