You can delete Media portal alerts if you no longer need to be notified when the alert conditions are met. (If you need to adjust the conditions, you can edit the alert instead of deleting and creating a new alert.)
From the main menu, select Network Tools > Alerts.
Media portal shows the alerts you've set up for your profile (if any). To view alerts for all users in your access group, clear the Show Only My Alerts checkbox.
On the row for the alert you want to delete, click the plus sign () or the link in the Alert Name column.
Media portal shows details for the alert: conditions that trigger the alert, the email address the alert is sent to, when the alert was created and last modified, and whether the alert is enabled or disabled.
Click Delete Alert, then click Delete again (in the popup that appears).