Role of the board chair
In an article 1, John Carver suggests a new title for the board chair of a policy governance board - the Chief Governance Officer (CGO). The CGO is responsible, not just for running the meetings, but "accountable for all aspects of proper governance (ensuring that governance proceeds in a way consistent with board policies on governance)..."
The CGO might chair the meetings, or might delegate someone else for that task. That would depend on the specific skills of the persons available. Carver says "Briefly put, the responsibility of this "first among equals" is to interpret and guide to fruition policies created by the board about its own job. Some of those policies relate to the discipline to which the board has committed itself, some to the mechanics of the board-CEO connection, and some to more philosophical matters. But in all events, the chair is more broadly a 'chief governance officer' than simply a convener of presiding official during meetings."
1 Board Leadership Number 56, July-Aug, 2001 On a Personal Note: The Case for a "CGO"