duty holder role on call exclusivity obligor role Sarah Bost on call exclusivity A duty holder role that inheres in a human being mentioned in an on call plan specification and that, if realized, is realized by its bearer participating a planned process realizing the concretization of the plan specification and being on call exclusively for the organization at specified times that is the contractual partner in the document act that created this role. A healthcare professional who has a primary obligation to a single facility while on call, however, in certain subspecialty instances, the individual may be on call at more than one facility, in which case a back up call schedule is required. Mathias Brochhausen