Hi Sarah

The behaviour when a Certification is assigned or recertfied is the course completion data is added to the Certification history and reset with the certificate archived. Allowing the 'View archive' permission for Certificates for the learner role should let the user see this.

However the Certificate isn't able to be deleted or regenerated  as it needs to be secure as this is the evidence of passing. This means to get a new certificate a new certificate activity to be added to the course .

A possible workaround for this is to select under the Issue options > Delivery for the Certificate force download or Email so the learner has a copy of the Certificate.

Regards