I was called to a commercial building to repair a walk-in cooler. Upon arrival, I found that the unit was not cooling properly. After further inspection, I discovered that the evaporator coil had frozen over. I thawed the coil using a heat gun and then replaced the damaged section with a new one. After completing the repair, I tested the unit to ensure it was cooling properly. The customer was very pleased with the work and thanked me for my prompt and efficient service.