Field help (OCNNUM) 

Once the supplier has received the order, enter the acknowledgement ID provided by the supplier.
After entering this information, the contract lines which have not been assigned an acknowledgement ID are automatically updated with this number.

Inter-company specificities: For inter-company or inter-site contracts, the Order acknowledgement ID and date cannot be accessed and are initialized, when the sales contract has been generated, with the date and the number of the sales order. You can use the Actions icon available on the Ack. ID field to jump to the generated sales contract, provided you are granted the proper authorizations.