Ability to edit page and attachment version change comments

We use Confluence to maintain specifications.  The specifications are long, complicated and change often, the changes are driven by JIRA.  It is important to know when a part of a document has changed because of a specific issue and to be able to match changes with issues in the document history.  However, users make mistakes in the change comments or forget to fill them.  We would like to be able to modify a missing or wrong change information after the page has been modified.