When it becomes necessary in the opinion of the Council or Administrator, in the event an Administrator has been appointed as provided in R.C. § 735.271, or a substantially equivalent municipal ordinance, in the prosecution of any work under contract, to make alterations or modifications in the contract, the alterations or modifications shall be made only by the Council by resolution or by the Administrator in writing, in the event an Administrator had been appointed as provided in R.C. § 735.271, or a substantially equivalent municipal ordinance, but the resolution or written modification shall be of no effect until the price to be paid for the work and material, or both, under the altered or modified contract has been agreed upon in writing and signed by the contractor, and by the Mayor or Administrator in the event an Administrator has been appointed as provided in R.C. § 735.271, or a substantially equivalent municipal ordinance, on behalf of the municipality. No contractor shall recover anything for work or material because of any alteration or modification unless the contract is made as provided in this section, nor shall the contractor recover for the work or material, or either, more than the agreed price. The law relating to requiring bids and the awarding of contracts for public buildings, so far as they apply, shall remain in effect. A duplicate copy of each contract shall be filed in the office of the Fiscal Officer.
(R.C. § 731.16)