1. Cancel Link button is
available when browsing linked posts. Clicking it returns the currently selected line of posting to the list of open
posts. This way cost center is deleted also. Below is displayed the message
which appears when trying to cancel the link:
In such a case general ledger and the Goods module, that is other
transactions, do not correspond anymore. In this case you have to repost the
document.
2. Similarly, there is Link Line
button available when browsing open posts.
Clicking it links up the currently selected line of posting with the cost
center. Cost center is entered in journal entry line. That is why the following
mesasge appears when trying to create a 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 automatically.
Clicking
you
cancel the operationp keeping the link between document and cost center.