With an account who is member of The Farm Admin SP Group you can browse to
http://centralAdminURL:port/_admin/Conversion.aspx or click Upgrade and Migration > Convert farm license type and add your new license key.
Now this is disabled by default and you have to use the developer tool to enable it. Clicking the input field, you'll see the disabled attribute. Change its name to something else (adding a few characters will do). Enter your license key, and turn your developer tool pointer to the OK button and do the same thing there.
This is probably not supported, and I'd advice you not to use this in production. But it's worth a try in your development environment.
Reference: How to Enable the convert License type option Under Upgrade and Migration.