Therefore, a role describes what an individual actually does. Every organisation will define those roles that it requires in order to perform the necessary tasks and will allocate individuals to perform those roles. The relationship between roles and persons is a many-to-many one (i.e. an individual may perform more than one role and a role may be performed by more than one person). Roles may or may not be related to job titles.
As stated earlier, there should be one role that is accountable for any specific task or process. ITIL advocates that four generic roles should be defined: