This function permanently removes a form instance from the list. We'd like to suggest archiving the form instance instead. 

You should navigate to the Run—Form Instances page and select the instance from the list. You may use the Search textbox to narrow the list. Then, click on the Action—Remove menu option.

The Remove Instance popup window is displayed for confirmation. Please note that this action is irreversible. If you're sure, you may click the OK button to confirm. 

The form instance is removed, and a confirmation message is displayed in the top right-end corner.