This work is concerned with localizing and analyzing the potential impact of changes to large-scale enterprise systems, and, in particular, how to incorporate reachability analysis and aliasing/pointer analysis to minimise false-positives and eliminate false-negatives. It is a continuation of our previous work, which included static analysis [1] and dynamic analysis [2] of changes to systems containing hundreds of thousands of classes and millions of methods. This current work adds: reachability analysis that examines the program to see “whether a given path in a program representation corresponds to a possible execution path”, such that infeasible paths of mis-matched calls and returns can be filtered out from the estimated impact set; and alias analysis to identify paths that are feasible but cannot be affected. Using our approach, organizations can focus on a much smaller, relevant subset of the test suite instead of performing their entire suite of tests without any idea as to whether any test is necessary. Also, in the future, we hope to be able to help testers to augment the test suite with new tests that cover the impacted methods/paths not already subjected to testing. We include a case study that illustrates the savings that can be attained.