When monitoring data in documents of Goods module and general ledger you can use cost centers for monitoring costs, income and expenses.

If you link up a document with a cost center, posting the document and cancelling the link (see Cancel Link in invoices issued and invoices received), the cost center is deleted from document line. That is why the following mesasge appears when trying to cancel the link:

Clicking you confirm the operation and any changes made get recorded. Yet general ledger and data in Goods module, that is, in other transactions do not correspond anymore. In this case you have to repost the document.

Clicking you cancel the operationp keeping the link between document and cost center.