How to remove postgres database from heroku

If you created the database with the web UI on postgres.heroku.com, you need to navigate to it from https://postgres.heroku.com/databases , then click on the gear icon on the right. There should be a destroy link. If you don't see a destroy link, then you probably aren't the owner and lack privileges.

It looks like you're missing the name of the add-on. Example:

$ heroku addons:remove heroku-postgresql:dev --app salty-river-24

Use heroku addons --help to view the help, or heroku addons to list the add-ons for your app.