US Airways’ Platinum and Chairman’s Preferred members can now purchase an upgrade for an Envoy Sleeper any time before their flight and receive an advance seat assignment for themselves and a guest by calling the Platinum or Chairman’s Preferred desk. The Envoy Sleeper is $300 when holding an Envoy class ticket — if upgrading from coach, the cost would be $500 more for a total of $800. Usually, these upgrades are available only on the day of departure at the airport.