In Volto can I set a default layout on already existing content?

In Volto can I set a default layout on already existing content?

I like that I can configure the default layout for a content type in Volto by going to:
Site Setup > Content Types > My Content Type (under the '...' menu) > Layout

After this, new content will inherit the newly defined layout.
...but, what happens if my content has been created already? Can I have the old content inherit the newly defined layout?

There's a good explanation of the layout editor in this video from 2021 (updated to link to the right timestamp):