How to convert theme.scss files to theme.css in Shopify themes?

[SkoorySquirrel]

Shopify is notifying shop owners about the need to convert theme.scss files to theme.css files. They are saying that all free and paid Shopify themes in the future will have this conversion. 

Ok, that's good.

Looks like a .css file can be saved as a .scss file but not vice versa. But, how am I supposed to convert our theme.scss to .css - there aren't any guides or anything provided. So, I just downloaded the most recent version of our theme, but that is still using the old theme.scss file that Shopify told me they do not want!

Can someone shed some light on this issue, pls. Thanks.