Use Tool #918 "Update Trans Desc & IRA/HSA Post Codes."  After entering the account number and suffix for the IRA account, you'll see a list of transactions for that account.  Simply highlight the item and click the "IRA/HSA Code" option.  The IRA Posting Type Update screen will appear showing details about the transaction and the processing code that was originally used.  To change the code, click the lookup button next to the New IRA process field and choose an appropriate code from the pop-up window.  When done, make sure to use F5-Update to save your change.