How do I configure an absence type to be for an open-ended duration (no end date) or for part of a day (e.g. less than half a day)?

Only System Administrators can configure a type of absence to be an open-ended or partial absence. Go to the left sidebar > Click on ''Administration'' Click on ''Absences'' > Click on ''Types'' > Select an absence type by clicking on it > Click on the pencil button next to the ''Options'' field > Select the option ''Allow to be a partial and open-ended absence''.