The swimlane format is a graphical arrangement in which all of the activities for a given role are shown in a single vertical lane. Each swimlane has activities, which are specific tasks that need to be accomplished as part of the process. A role is a subset of the activities in a business process that is performed by an actor, which is a person, group, department, organization, or information system. The name of the role is written at the top of a swimlane, not people's names. This is because a given role may be fulfilled by many people, or the organization may change the people who are assigned to a given role.