Reverting a paid theme to its default

[KenLee1]

I recently bought a new theme from Envato (not from the official store). After applying to Shopify, the new theme took on the old shop structure. I have purchased the new theme simply because the architecture is what I needed. Hence, I need help in reverting the new paid theme to its default. 

I have searched high and low on discussion forums, however, the only way reverting to default can be done for themes that are bought from the official store.