You can only delete custom contexts (not native ones).
Delete a context
Click on the [⠇] icon in the top right hand corner of the context you want to delete.
Then click on [Delete].
Confirm your choice on the popup that appears, and voila!
🚨 If you delete a context, the readers in a scenario within that context will be assigned to another custom context or the default context, depending on what was specified in your Poool configuration.
They will also be assigned to a new custom or native group (again depending on your configuration) and will start a scenario from the beginning.