Change the status to Reconciled Status. This will give you an overview showing what each entry is reconciled against.
If you have reconciled against the wrong item, you can undo the reconciliation by double-clicking the item you want to undo.
The reconciliation opens, and you will see the entries that are reconciled against each other.
Click the Undo button to undo the reconciliation.
The entries will then appear under Open items and you can reconcile these again as you wish.