Occurs when a previously conditioned response decreases in frequency when the cs is presented in the absence of the ucs

The answer is "extinction". 

Extinction is seen in both operantly conditioned and classically conditioned conduct. At the point when operant conduct that has been already strengthened does not delivers fortifying outcomes anymore, the conduct quits happening. In classical conditioning, when a conditioned boost is introduced alone without an unconditioned jolt, the conditioned reaction will inevitably stop.