Complex sentence: Despite the failure of the initiative in 2012, the question was put on the ballot again three years later, and Millcreek residents voted for incorporation on November 3,2015.
Split into simpler sentences: Despite the failure of the initiative in 2012, Millcreek voted again on whether to become a city in 2015, with the vote going the other way this time. Millcreek officially voted for incorporation on November 3,2015.