Admit that you have made a mistake accordingly. Consult with your manager or task leader about possible ways to resolve problems and prevent from happenning in the future. Ask for tools and resources that can help you and other organizational members to avoid the re-do work assignments. It's a waste of time and organizational resources to go all over and doing the same. Making mistakes can hurt you, whole organization, client or customer, and other constituents who may benefit from work or task you do.