I think the typical solution to this problem is to allow users to list and edit their records using the same recording form that submitted the original records. It may still be the case that they are effectively deleting the wrong occurrence and adding a correct one behind the scenes. However, it puts the task in the hands of the recorder rather than the administrator, which is preferable.

Another solution, if you are using the Drupal iFrom module, is to add content, create an iForm page, select "Utilities" in the form category and then the form, "Change identification of a record". I haven't used it myself. This would be an administrator task and you would want to use Drupal permissions to limit access to the form.

I am also aware there has been discussion about allowing verifiers to change identifications using the verification interface rather than notifying recorders of a mistake and hoping they will correct their submission. A new version of the verification form is about to be released but I am not sure if it incorporates this function.

Regards,
Jim Bacon.