Whenever a district has been established or is being established and a mistake has been made as to the number of acres assessed to the owner of any tract of land embraced in the district, the decree in the cause fixing or adjudging the number of acres shall not be final until the assessment roll provided by statute to be made by the directors has been reported to the court by the directors and decree has been entered confirming the acres; and when any such mistake shall have been made, the aggrieved person may file a petition in the county court in which the cause is pending, seeking to have the mistake corrected.