Steps:
1. Go to developer console.
2. Press CTRL+E
3. Enter below query the apex window and click on “Execute”.
Id recordId = 'IdoftheaffectedRecord';
Approval.unlock(recordId);
For example:
4.Once the record is unlocked, you can see the changes in audit trail report.
Please inform in case of any queries or if we are good to close the request.
Regards
Jogendra