Iron Patriot is an alias used by two characters in the MCU who have worn the Iron Patriot armor and used its capabilities for their own goals.
War Machine temporarily re-branded as Iron Patriot, used the armor in an effort to stop Aldrich Killian's illegal activites. A few years later, he returned to using the War Machine armor and alias simply because...he liked the older identity on a rule of cool.
(Though more likely it was because Whedon simply ignored the events of Iron Man 3 and preferred to revert his characterization back to the earlier War Machine self to make "Age of Ultron" more of a direct sequel to his original Avengers film with the characters designed in the way he preferred them to be.)
Green Goblin took custody of the decommissioned suit and used it as his cover as the leader of the Dark Avengers.