65 ILCS 5/4-5-17

If, at the beginning of the term of office of the first council elected in a municipality after that municipality has adopted the commission form of municipal government, the appropriation for the expenditures of the municipal government for the current fiscal year has been made, that first council shall have the power by ordinance to revise or repeal that appropriation and to make an additional appropriation in the manner and within the time provided by law.