In my point of view you must consider revising the business requirement of the process.If you use any movement with reference to PO (like 102 or 122) it will reopen the inbound delivery. So your requirement is just do a goods issue of stock or is a return to vendor? It can be handled by many ways like below:
1) You can implement a BADI in material document MM, and delete the Inbound Delivery after post goods movement throught MB01.
2) If this process is a return to vendor, you can work using a Return Purchase Order (flag inside PO - EKPO table) so it will allow you to post a return using another PO (only for return) and 161 movement (that will not reopen the inbound delivery). It happens because is created another PO just to do the movement.
So as I said, share with us the business requirement and we will be able some options for you.
Regards.
Gian