Credit card prepayment holds

 Hi - how does the prepayment authorisation and settlement holds work on the P4210? At what time does the order go on hold and at what time are the holds release? Typical scenario - user enter an order for a credit card customer. The request is sent to the credit card agent for authorisation and authorization hold get released. At time of shipment another request goes to the agent for billing and the settlement hold get release. At what time the order goes on settlement hold and how are the holds release. Any information appreciated.