To delete a configuration, tap the Edit button at top right. When the edit circles come up, tap the one next to the configuration you want to delete. This pushes the configuration name to the left and brings up a Delete button.

Or while in the main list of configurations, swipe a finger over a configuration name from right to left. This also brings up the Delete button.

Tap the Delete button, and the configuration will be removed from the list. Tap the Done button to cancel the delete operation, or when done deleting configurations.