In certain situations you may want to send the employee or manager responses back to draft.
For instance, in the default self-then-manager workflow, an employee cannot reopen their review if the manager has already pressed Submit. To override this, you can simply send the responses back to draft.
On the Appraisals page, press Edit next to the reviewee in question.
Use the Workflow button in the top-right corner to reopen the review.
After clicking the Reopen button, choose whether you want to send responses back to draft for reviewee, manager, or both.
If the deadlines have already passed for one or both parties, you may want to consider extending them as the reviews will be sent back as "Overdue" and the respondents will only have one chance to use the Submit button again.
If the review has indeed been shared at this point, you must first un-share the review. Similarly, if the review has been approved (optional workflow item), you will need to revoke approvals as well.