At some point, to meet the regulatory deadline, projects are scoped and the scoped objectives are added as a separate project initiative intended to be completed after the merger and to close the M&A as a successful project. During a large merger and acquisition project, two major financial institutes merged using a big bang approach on changeover day. Despite the merger scenario tested several times across the entire portfolio, the increase in volume did not make it possible to cope with the publication of the transaction on time, which caused inconvenience to the client. Despite doubling the large capacity of the system to resolve the problem overnight, the problem lasted for a few days, causing the brand's reputation in the following months. Many lessons were learned during the failed project and the failure was attributed to a poorly thought out transition strategy, failing to capture a key schedule risk such as mid month versus end of month/ end of the quarter, identifying the key risks involved in a gradual rollout versus a large rollout. bang approach and have a test system identical to real production