To Delete Management of an API Version (Nov 2017)
The procedure removes the capability to manage an API Version from API Manager. If the API resides in Exchange or on the file system as a ZIP, it isn’t deleted from Exchange or the file system.
In Anypoint Platform, click API Manager.
In API Administration, click the API version link or an instance link.
Select Delete from the Actions dropdown.
Respond to the prompt to confirm the deletion. Click Delete.