Rochester Mayor Lovely Warren has agreed to resign for violating state election law during her 2017 run for re-election and will leave office by Dec. 1.Warren, 44, was readying Monday for what was expected to be a month-long trial on felony charges that she and two assistants violated campaign contribution limits, but she pleaded guilty to a single misdemeanor, admitting that she knowingly exceeded the $8,557 limit, the Democrat & Chronicle reported.