How to remove the postgres database from heroku, which was created using the free dev plan. https://postgres.heroku.com/databases
I tried to use the hero add-ons: remove --confirm --app salty-river-24 but he says that the application was not found. This is the correct syntax.
If you created a database with a web interface on postgres.heroku.com, you need to go to it from https://postgres.heroku.com/databases , then click on the gear icon on the right. There must be a destroy link. If you do not see the destruction link, then you probably do not own and do not have privileges.
It looks like you are missing the name of the add-in. Example:
$ heroku addons:remove heroku-postgresql:dev --app salty-river-24
Use heroku addons --help to view help, or heroku addons to list add-ins for your application.
heroku addons --help
heroku addons