Style generator - How to overwrite

[sulasno]

I created a new style and saved it under a new parent; How do I edit the new style ?

I created another style and saved it under an existing style and when I click Save, I get

A style called 'Red' already exists. - To use this style file, either overwrite the style called 'Red', or enter a different title on the upload form.

How do I overwrite ?

[Agathadaimon]

A different theme on an existing theme, I want to print?