Malaysia Airlines is one of the carriers that allows you to bid on an upgrade ahead of time and will notify you ~ 48h prior to departure if it was successful, in addition to instant upgrades that are sometimes offered.
Upgrade Bidding has been adopted by a good number of airlines that seek to sell their leftover Business Class and generate additional revenue on seats that would have otherwise gone out empty by cut-off time.
A great solo travel tip spotted this week on LoyaltyLobby.
