Fairly straightforward:
git remote rm origin
As for the filter-branch question – just add –prune-empty to your filter branch command and it’ll remove any revision that doesn’t actually contain any changes in your resulting repo:
git filter-branch –prune-empty –subdirectory-filter path/to/subtree HEAD
Remove existing origin and add new origin to your project directory
>$ git remote show origin
>$ git remote rm origin
>$ git add .
>$ git commit -m “First commit”
>$ git remote add origin Copied_origin_url
>$ git remote show origin
>$ git push origin master