The IMsgServiceAdmin::RenameMsgService method assigns a new name to a message service. This method is not currently supported.
See IMsgServiceAdmin : IUnknown.
HRESULT RenameMsgService(
LPMAPIUID lpUID,
ULONG ulFlags,
LPTSTR lpszDisplayName
);
Clients wanting to assign a new name to a message service should assign a new name to its PR_SERVICE_NAME property. The names of service providers in a message service are stored in their PR_DISPLAY_NAME properties.