上海市嘉定区人民政府

企业环境应急预案有重大修订的，应当在发布之日起20个工作日内向原受理部门变更备案。变更备案按照《企业事业单位突发环境事件应急预案备案管理办法（试行）》第十五条要求办理。

Answer: If there is a major revision of the enterprise's environmental emergency plan, it should be filed with the original acceptance department within 20 working days from the date of issuance. The change filing shall be handled in accordance with the requirements of Article 15 of the "Administrative Measures for the Filing of Emergency Response Plans for Environmental Emergencies of Enterprises and Institutions".