The healthcare domain is in urgent need for solutions to making clinical and administrative systems, possibly belonging to different healthcare units, interoperable and hence making them deliver timely and correct information as needed in particular situations. Process manager technology allows making all actors (humans or information systems) involved in healthcare processes communicate along these processes. This paper argues that process manager technology is essential for achieving interoperability in healthcare, but that some serious problems need to be overcome to realise its full potential. A number of design solutions to address these problems are proposed.