Ohio Revised Code Title I. State Government § 153.11

Whenever the change referred to in section 153.10 of the Revised Code is approved by the owner as defined in section 153.01 of the Revised Code, accepted in writing by the contractor, and filed, the same shall be considered as being a part of the original contract, and the bond theretofore executed shall be increased or decreased accordingly to include and cover the change in the contract.