Tutorial Step 14: Splitting Tasks
If a resource begins work on a task, but needs to finish the rest later, the task can be split to continue at a later date. For example, if a resource needs to switch away from a partially-completed task and then switch back, you can split the task.
To split a task:
Select the task in the outline.
In the popover, enter the amout of work completed and click the Split Task button; the task is split for later completion.