If an employee is unable to make further edits to their self-assessment, then there are a few things to check to ensure that the employee is able to continue editing.
Ensure the cycle is still open
To ensure the cycle is still open, you'll need to visit the cycle Timeline settings allow the employee to still edit their review. Below is a screenshot showing this date in the Timeline setup portion of the cycle setup.
Locate the cycle setup from the overview screen:
Check the self-assessment editable until and the sign-by date to ensure everything is still open:
Revoke signatures and re-open the review to allow editing
If the review is closed, you can revoke the signature and re-open the individual review to allow further editing. Below is a screenshot showing this option from the overview screen.