Most email templates in ILLiad 8.4 and later can be stored and edited in the Customization Manager, but there are a few that are stored on the server. The specific server side email templates such as elecdel are listed on Atlas System’s guide to Creating and Editing Email Templates for ILLiad.
So how do you edit these templates if OCLC hosts your ILLiad instance and you don’t have direct access to the server? It turns out that you can edit the template to your liking and email OCLC support with the new template. They will then upload it to the server for you. Viola! your email template is updated!