As a business analyst, an important part of your role is to decide if a solution is the best possible one for the problem at hand. But here's an interesting question: How ready is the organization to accept the best solution? Solutions that "work" technically, but are resisted by their intended users, can't be said to be entirely successful. That's why another important part of your role is to gauge the organization's readiness for the solution, and devise ways to help the stakeholders become comfortable with it.
The first step is to evaluate the differences between how things are today and the way they'll be when the solution is implemented. This will help you decide where to focus your efforts to help achieve organizational readiness. For example, will the solution introduce a new process, technology, or tool? If so, the second step might be to evaluate the kind and depth of training the staff will need to take full advantage of the new technology.
If the solution will create a new role, you'll need to find out if the staff has sufficient training, knowledge, expertise, tools, and so on to perform the duties of the new role. If the solution involves eliminating a role or function, you'll need to consider what will happen to the people who'll no longer perform the role. If the solution involves a paradigm shift in the business culture, you will need to evaluate and help change the current management processes.
As part of your project test plan you should include user acceptance testing, to expose the users to the new solution and devise ways to help them get ready for it. To ensure that the staff formally acknowledges their acceptance of the solution, consider putting a formal phase signoff process in place.