API - detach email from its template

Level 2

API - detach email from its template

In Marketo's UI, you can "detach" an email from its template by editing the html.  Is there a way to do this with the REST API? 

I only see the email content endpoint which allow you to update editable sections, but not the HTML.  Being stuck with this template to email association in the API is very limiting, we send a large number of significantly visually different emails and every time we have to create a template for a unique usage, its clogging our instance with thousands of unnecessary templates.

It seem like the only way to change the HTML structure (and not its content) is by editing the template, then re-approving it (which the API takes about 300-500 seconds to execute for us) and then create a NEW email for it.