The Reconciliation tab lists outstanding withdrawals (checks, credit card payments, transfers, and posted bank entries) that have been entered for the bank in Bank Services or sent from Accounts Payable or Accounts Receivable (as refunds).
During reconciliation, you can clear withdrawals with different reconciliation statuses, or you can leave the withdrawal outstanding. More...
You can also use the Reconciliation tab to reverse payments that were sent from Accounts Payable or Accounts Receivable.