When you in the Agent portal choose Delete all personal data on Tickets & Orders, all fields that are set as personal on Tickets with status marked as a close-stage, are emptied. Data is erased directly, no request is created.
As End user you can in SSP under the User profile menu choose Personal Data Protection > General > Delete personal data Tickets & Orders > Request deletion, an enquiry about this to the system GDPR handler. When he or she has approved your request all personal data is deleted on closed tickets and on the orders that are connected to closed tickets.
Personal data on the system account is not affected. Is you want to delete this data use the alternative Forget me on this system.
You can see what requests you have made by surfing to User profile menu > Personal Data Protection > My Requests.