NOTE: Alerts always operates in the confines of the current site collection. This is why you will only see the existing alerts coming from the current site collection. To see additional alerts you might have created in other site collections, open the Alert Settings management page from a site in that site collection.
The Existing Alerts section shows the alerts previously created by you in the current site collection. You can edit any alert or delete one, some or all alerts.
NOTE: : Site Collection Admins see all users that have alerts throughout the site collection and can manage everything from a single location. Site Admins (Site Owners) can only see alerts of users who have alerts within the current site, where they are Site Admins ( Site Owners).
All alerts / Current list toggle allows to switch between showing all the alerts in the current site or only the alerts for the current list. The toggle will be disabled, when this page opened from Site actions or Site settings.
When you click on Edit, the alert will be highlighted and the properties of the alerts will be loaded into the sections below. Once done editing, you can click on Update to save the alerts or on Cancel to undo the operation.
