I just spent couple of hours banging my head against the wall with this one. The requirement was clear. If the A002 relation for an existing position is changed, I should trigger a workflow and send out a notification. Easy, right? I ended up searching SCN and I was surprised to see that there are many discussions on the topic and no solutions.
What you will need to do is go to SWEHR1 and enter the configuration for S-1001-A002.
Next you will have to go to SWEHR3 and enter the configuration for S-1001-A002. Notice however that the action type is not UPD, it is DEL + INS. This is the tricky part! You can configure until pigs fly but UPD won’t get you anywhere.
Copy the template function module HR_EVENT_OT_NNNN_UUUU_TEMPLATE to create your own function module.