I'll start by borrowing some comments from @gmclemm on a similar question: Are you sure you want to do this? Fixing the defect and verifying the fix are different activities, clearly in your case carried out by different people. Might it be better to use an Approval to track the testing (so the defect manager could create an approval and assign it to a tester)? Or use a child or related work item for the testing activity (allows you to track time and have independent discussion)? If the verification is not successful, how do you know who to return it to if you changed the owner? It would be easier to change the status to Re-opened and have it show back up in that person's queue than search the work item's history to see who the previous owner was. All that said, here is an example using a JavaScript customization that sets the owner to a particular value when the work item is in a particular state: https://jazz.net/wiki/bin/view/Main/AttributeCustomizationExamples#Automatically_set_the_value_of_a