Computation Tree Logic (CTL) model update is an approach for software verification and modification, where the minimal change principle is employed to generate admissible models that represent the corrected software design. In this paper, we apply CTL model update to models based on the well known Andrew File System protocols. We demonstrate the process of model update based on our previous theoretical results, and present a prototype implementation. Our case studies show that our model update system is sound and workable, which can be applied to different complex systems.