The organizations are using Enterprise Resource Planning (ERP) system to run the business, services, human resources, and manages back-office workflow. ERP system is dynamic, complex, larger in nature and used for the implementation of technological and organizational interactions. In ERP implementation, two types of approaches are used including Big bang approach (traditional) and Agile approach. ASAP is a form of Big bang approach of software development, which highly focuses on documentation, more suitable for stable requirements and difficult to manage change. ASAP methodology works in phases including Project Preparation, Business Blueprint, Realization, Final Preparation and Go live and Support. Business blueprint is a critical phase where business requirements are analyzed and documented in AS-IS process. During the AS-IS process users provide the requirements and vendor map these requirements in TO-BE with the help of IT experts. At start, lack of the domain understanding of the end user may lead to vague and incomplete requirements. This situation creates deadlock between the user and vendor which delays the process, increase the cost and disturb the schedule. Moreover, due to the conventional nature of ASAP methodology, it becomes difficult to manage change at later stages of software development. SCRUM, being one of the major forms of Agile, provides support for change acceptance during and after development. SCRUM also provides practices for better requirements management at different stages of development. We have proposed an improved and hybrid methodology which will ensure the correctness of requirements capture. For this, we have investigated the issues attached with the ASAP methodology due to which, vague and incomplete requirements are generated. We have introduced suitable practices of Scrum to minimize the shortcomings of conventional ASAP methodology. The proposed solution has been validated using case study of GEPCO (Gujranwala Electric Power Company) ERP project. This case study has compared the productivity and defect occurrence in Blueprint phase using conventional ASAP and Hybrid ASAP methodology.