Issue
I have a long running Release Phase process running that I need to stop and prevent the release from completing successfully
Resolution
Release Phase processes are the same as any other Dyno in your formation, expect they run the codebase from the new release, instead of your current release.
To monitor your Release Phase processes as they execute, you can use the CLI command heroku ps -a YOUR_APP_NAME. as these are normal processes, you can use the ps:kill and ps:scale commands to stop the Release Phase from completing, which in turn, will prevent the latest release from completing.