Problem: Created a new 'Create New Event' event policy to change Alert Severity of specific alerts, the policy is working as it creating a new Alert with desired Severity but the old Alert is not getting cleared. Hence, SOI console has both old & new alert.
Solution: Change Mdr Element ID event value from default " fx:uniqueidentifier() " to " ${pattern1.MdrElementID} "
This changes helps ensure that a new event is created with a unique mdrElementID value.