  Requirements Engineering (RE) is a key activity in the development of
software systems and is concerned with the identification of the goals of
stakeholders and their elaboration into precise statements of desired services
and behavior. The research describes an Agile Requirements Engineering approach
for re-engineering & changes in existing Brownfield adaptive system. The
approach has few modifications that can be used as a part of SCRUM development
process for re-engineering & changes. The approach illustrates the
re-engineering & changes requirements through introduction of GAP analysis &
requirements structuring & prioritization by creating AS-IS & TO-BE models with
80 / 20 rule. An attempt to close the gap between requirements engineering &
agile methods in form of this approach is provided for practical
implementation.
