The role of the knowledge manager is a governance, assurance, information, and champion role, making sure people are working with the knowledge that they are supposed to have.
They make sure that the expected knowledge management technologies are applied at the right time, that people get the knowledge they need, that this knowledge gets applied and that new knowledge is captured and shared, and that information can easily be retrieved apon search.
They monitor the processes of learning before, during and after, working by mentoring, coaching, and prompting to make sure these processes happen.
In project management, Each of the projects in the company has to assign assign somebody to take the role of knowledge manager, to prepare and deliver the project knowledge management plan, and to ensure that the lessons capture session are held and attended by all staff.
This applies also in the daily operational work. If you can help a team to learn, and to share their learning, then you can help them not only to improve, but also to help the rest of the business improve as well.
One of the more common reasons for failure of knowledge management initiatives within organisations has been the absence of this sort of role. If no one takes the accountability of such a role, then all too often knowledge management never takes root, even if everybody knows knowledge management is important. Take away the Knowledge manager role, KM suffers, just as safety would suffer if you removed the safety roles, or financial management would suffer if you removed the finance roles.