When a modification is made by a prospective modification order, you need to know when it starts and stops. It begins to apply when an epidemic management notice says it is activated. This can happen in a few ways, such as when the notice activates the specific modification, all modifications made by the order, or all modifications made by any modification orders. You also need to know when the modification stops applying. This happens on the earliest of a few dates, such as when the epidemic management notice that activated the modification expires. It can also stop when the epidemic management notice or part of it is revoked, or when the order itself is revoked. The modification's application is controlled by these rules, which determine when it starts and stops.