48 CFR §1942.202-70

The Contracting Officer may designate an appropriately qualified Government employee to act as the Authorized Representative of the Contracting Officer (AR/CO). Such designation shall apply to a single contract, must be in writing, and shall define the scope and limitations of the AR/CO's authority. The instrument designating an AR/CO shall not contain authority to sign or agree to any contract or major modification to a contract. Contractual commitments shall be made only by a duly certified contracting officer. The Contracting Officer shall insert the clause at 1952.242-70, Authorized Representative of the Contracting Officer, in solicitations and contracts when an individual is to be selected and designated by the Contracting Officer to perform administration of a given contract(s).