Reconciliation is how Modern Treasury matches payment orders, expected payments and returns to your bank statement. Behind the scenes, Modern Treasury works to ensure that we track a payment order from its creation to completion in order to reconcile to the appropriate transaction. You will know a transaction has been reconciled when you see the green check mark on the Bank Statements Page.
Payments initiated outside of Modern Treasury that don't match to an expected payments will display a yellow dash next to them. You can still reconcile manually by creating an expected payment and then manually reconciling to the transaction (see this article for how).