changes the obligation in favor of one party against another, either by enlarging or reducing the obligation.” Id. at 444-45, 733 P.2d at 641-42. ¶ 116 Although the introduction of competition may affect the income stream to AEP-CO, the parties’ obligations under the all-requirements contracts are not changed “in favor of one party against another.” Id. The distribution cooperatives are still required to purchase all their power from AEPCO, which must supply this power. For this reason, competition in the generation market does not impair any obligations under the contracts, and the superior court properly entered judgment against the Cooperatives on this claim. Cf. Earthworks Contracting, Ltd. v. Mendel-Allison Constr. of Cal., Inc., 167 Ariz. 102, 108, 804 P.2d 831, 837 (App.1990) (<HOLDING>). ¶ 117 The all-requirements contracts also
holding that contract charged primary contractor with a duty of care for all employees on the work site including employees of its subcontractors where contract required primary contractor to comply with applicable state and federal safety statutes and regulations made primary contractor responsible for reviewing safety programs of its subcontractors and primary contractor employed a safety officer to oversee its subcontractors operations holding that application of licensing statute effective after unlicensed subcontractor entered construction agreement with contractor would impair obligations under the contract because contractor would be relieved of its obligation to pay for subcontractors services holding that where contract between contractor and subcontractor allowed subcontractor to recover if contractor recovered contractor was not barred from bringing suit on behalf of subcontractor holding in part that the liability insurance company of the subcontractor which had named the general contractor as an additional insured on the subcontractors policy was liable to reimburse the general contractor for a settlement payment the general contractor had made to the subcontractors employee holding that bankruptcy trustee for contractor could not avoid prepetition payment of funds from contractor to subcontractors