A phase is a set of tasks, which signifies the completion of a project segment. You can use the Phase function to divide all the tasks in a process into sets of tasks (or subtasks). For example, in a typical Sales process, all subtasks which help achieve Customer Prospecting can be considered a phase.
Phases are represented by vertical lines and are similar to implementing Swim lanes (as discussed in
Using swim lanes. You can define a Phase and its worksteps in the
Diagram tab. In the
Overview tab, you can view the phase to which a particular task belongs.