Changes seem to be inevitable. No matter how we try to postpone the decision making and extend implemented system lifecycle, eventually the inherited information system stops to comply with business needs. The new system modelling is based on re-engineering when the existing system is being transformed to optimise both business and maintenance processes.
There is no perfect recipe for requirements management, and development teams should be flexible. However, if in a traditional development project using a particular methodology is fairly transparent, then in re-engineering projects, involving a significant upgrade or information system replacement, teams face to a "snowball" of requirements that can negate the primary purpose of the transition.