Audit templates are managed in the audit library, which you can access by selecting following from the menu
Audits > Settings > Audit library
An audit template can be deleted from the library or edited as long it is not in use in any audits. If audit template is in use in audits, it is possible to define, that the template will be hidden. Then the audit template will not appear in the dropdown menu in the auditing process, which means it cannot be used in any audit.
Find the correct audit template in the audit library. From the three dots icon select Edit
In the editing view empty the selection on Audit form is in use and click Save