EUA = Elite Upgrade Automation.
It's an acronym coined in 2001 when CO developed the current system of their computer systems automatically upgrading elites, which replaced the old system of elites having to call to request an upgrade after midnight on the day that each elite level's upgrade window opened.
While the acronym technically refers to the software CO put in place to do this, the name stuck here on FT to refer to CO's complimentary elite upgrades.