How to begin with notifying DWP of changes to capability

Just wondering where and how to begin with notifying DWP of changes to the claimant's capability. The claimant has got significantly worse recently and I haven't a clue how to begin the process. I've looked in the guides but I can only find information on dealing with reviews.

Any help greatly appreciated Thanks

Hi David, no, there's been no WCA or PCA since the original decision, some ten years ago now, when they did have a visit from a HCP; the report was of course full of lies on their behalf and we won eventually on Tribunal. The award was for an indefinite period, and the claimant has been left alone by the DWP since then.