If the retro has happened already, changing IT0003 is not enough. Cluster data already created need to be deleted accordingly.
It's really important you get this right in your test runs and add the respective steps to your go live plan to have IT0003 as you need it first time round for production. You'll need all retro-triggers empty and retro pre-go-live blocked. You don't want to get into the situation to delete clusters in production, as auditors will not like that.