No, the only required role in a workpaper is the approver.
Preparer: Optional. Assign this role to team members responsible for preparing the workpaper.
Reviewer: Optional. Assign this role to staff who review the work completed by the preparer.
Approver: Mandatory. The approver is responsible for finalising and certifying the workpaper.
Additional Information
The reason we don’t require all three roles is that higher roles inherit the privileges of lower roles. This ensures that all job requirements are still met, even if one or more roles are unassigned.
A reviewer can do everything a preparer can, plus review the workpaper.
An approver can do everything a reviewer and preparer can, including final certification and approval.