Hi:
I've moved this to your Premium Support Portal where we can better help you with specific steps to try.

Generally, and for others' reference, you may be able to return to the edit interface (or delete action) by opening the same action for a different assay, then grabbing the "controller-action?parameters" part of the URL and substituting the name or ID of the 'broken' assay design to target the one you want to edit (or delete) instead.

Learn more about URL structure and components at this link.
--Molly