A role in the organization is a title or job function which is associated to a set of activities performed by participants of the organization.
Examples of roles include Accounts Manager, Sales Clerk, or Customer. Roles are similar to job titles, but are more flexible because a participant can be assigned to several roles, and some roles, such as Customer, may not be jobs at all.
Every interactive activity is defined under a role. This is done by placing the activity within a swim lane with the name of the role. Swim lanes with no role name are only used for automatic activities which require no user interaction, and are not assigned to a role.
Participants are assigned one or more roles. This is how the process can determine which participants can execute a given activity.