Realistically? They'd start asking me how my things are going, and then I'd give some vague general comments and instead ask them how their things are going and then we'd talk about their things. Not sure what to do in the symmetrical case. Maybe try to find non-personal topics to discuss (e.g. books and other fiction, politics, anything else) with the major challenge being finding out which topics both people are interested in (and don't disagree too much on).