Source Agreement read-only on existing PO line during change order

Hello,

We are trying to determine whether it is possible to assign a Source Agreement/CPA to an existing PO line through a change order.

When we create a change order for an approved PO, the Source Agreement field on the existing PO line is read-only. We are seeing the same behavior in both Classic and Redwood Purchasing.

We reviewed Oracle documentation that lists Source Agreement and Source Agreement Line as attributes that can't be updated after a purchasing document is implemented. However, we also found Customer Connect discussion 955395, “Cannot add agreement at PO line when supplier site differs from agreement site,”