Impossible to add a contrat to PO item even if invoice has been cancelled

Question

Hello Experts,
I want to add to an agreement (EKPO-KONNR) to my purchase order. Initially there was an invoice on the PO item which I cancelled.
Transaction ME22N :
The agreement and agreement-item fields remain greyed out on the screen.
I tried the transaction MASS:
I works fine when my agreement has just one item. But if it has more than mone item, my purchase order is not modified.
After debugging, we found out that if the PO has history data, it does not accept any agreement except when the agreement has just one item.
The goal is to add an agreement to such a purchase order.
Can someone please confirm to me that what I actually want to do : is it possible and is there any other way possible to do this ?
Thanking you  for your sharing your ideas!
Mahesh

Answer 1

Hello Mahesh,
If follow-on documents already exist for a purchase order, changing the        
purchase order is generally a problem. Therefore, you should consider          
the changes and the possible consequences carefully. 
The field EKPO-KONNR is not available for input after a GR regardless of whether        
this is reversed or not.                                                                             
The only real option open to you would be to delete the existing line and create a new line or a new PO.                                           
Regards,
Mauro