What must the Owner do with respect to removing/ replacing defective or inferior equipment, materials, or work?

If the Owner is: (a) authorized by the Contract or General Conditions to require the Contractor to remove or replace defective or inferior materials or equipment or to replace bad or defective work; and (b) represented by a professional duly authorized to supervise the Contractor's work and to exercise the discretion and authority of the Owner, the Owner shall promptly condemn (seize) such materials, equipment or work in order to minimize the damage or loss of the Contractor.

However, where even with the exercise of due diligence, the Owner could not have discovered the use of inferior materials and equipment or the defective work, the Owner shall promptly  condemn it upon discovery, and the Contractor shall bear all the cost of removing and replacing the defective or inferior material or equipment or work.