All organisations need to implement change. Managing the introduction of change efficiently is important as it helps to make sure that change is successful. Like many others, I've found that using a structured methodology helps to embed change. Broadly speaking, projects (whatever method you use) will need to go through four stages to make sure the change is successful:
You need to define the change you want to make. What will be different about the organisation once the change has been made. How will you know that the organisation is different and that the change has been successful.
Once you've defined what you need, you'll need to design a solution, or a way of making the change. As part of this process you'll need to understand what's happening currently so you have a starting point from which to plan the change.
You'll need to deliver the solution. If you've defined and designed what you need to do that'll help this part of the process enormously.
When you've completed delivery you need to develop your understanding of how well the process of introducing and embedding the change has been. Then you can work out if there's anything that can be done to improve next time. This is an important part of any change but one that is quite often omitted.