There is no way for individuals to delete instance records in Inventory at this time. We may be able to delete them through a batch process.
If you have created an instance in error, you can mark it for deletion (to be deleted eventually by a batch process).
First, make sure there are no holdings or item records associated with the instance.
In the instance detail view (right pane), select Actions→Edit.
Check the boxes for "Suppress from discovery" and "Staff suppress":
Add the "Delete" statistical code:
Save and close the instance record.