Have not tested this, but you should be able to redirect the task form Management Worklist to the new user, this way the task will be on the users task list and the notification should now use that users email address.

If the process is in Error state you may have to repair it first or do a GOTO to the client event, this will make the escalation to be re-planned, meaning if the goto is performed the escalation mail will fire to the new use.

Please let me know if this works.

HTH

Vernon

I’ve found this Important Notes in K2 blackpearl  Developer Reference help pages. Hope it will be useful to fix this issue

 (note: this scenario does not reflect Best Practice since the destinations are hardcoded, so this example is only for illustrative purposes)

A process definition has a specific user hardcoded as the destination user for an activity. Several instances of the process are created, and worklist items are created for the user. During this time, the original user leaves the organization, and the process definition is updated so that the original user’s replacement is the new destination user for the activity.  You can migrate the existing instances of the process to the new definition, but the worklist items will not appear on the new user’s worklist – the reason is that the DESTINATION RULE for the activity in question has already executed.

In order for the worklist items to appear on the new user’s worklist, you will need to perform a GoToActivity call on the existing instances after migrating the existing instances to the new version of the process definition. You will specify the current activity name as the activity to go to – this will force K2 to recreate the activities from scratch, and all the rules will be reapplied to the activity in the sequence mentioned above. Therefore, the new destination rule is executed and the worklist items will appear on the new user’s worklist.