Makes me wonder: Don't they want to get better? Does the physical therapist care anymore?
Most times--depending on the findings you are trying to fix--it can be perceived by the client as discomforting, wasteful, and boring. Lets face it...clients receive a larger "effect" from flipping a tire, throwing medicine balls, or executing some inchworms than they would performing lateral band walks, hip bridges, and side planks.
Here are a couple of tried and true tricks to expose your clients to corrective exercise without actually emphasizing the need to set aside an entire "phase"in their program.
Hope this simple ideas help you out. the term "corrective" can be interpreted in many ways. I tend to view my physical therapy drills as "corrective"; but mots trainers will deem exercise that address muscular imbalance as corrective. Some may even look at some movement prep work as corrective. Whatever the case, make any phase of your overall program fun, engaging and most importantly...effective.