Yes, you can certify on behalf of another role if your assigned role includes the permissions of the below role.
Role Hierarchy and Certification
In Cimplico Workpapers, roles inherit the permissions of roles below them:
Preparers can certify only as preparer
Reviewers can certify as reviewer and on behalf of preparers.
Approvers can certify as approver and on behalf of preparers and reviewers.
In the example below, the Demo User is an approver, so can certify on behalf of the preparer and reviewer.