In fact, when the starting position of the defaulting country is a primary fiscal deficit, a marked move into a primary surplus is also required, as the country usually has no longer access to borrowing in the aftermath of a default.
To complete a payment, the banks behind the transaction need to transfer funds between each other. Until this happens, the payment between them is like an “IOU.” Today’s systems that transfer funds between banks are not set up to work in a 24/7, realtime world. Instead, most faster payments settle funds between banks on a deferred basis.