Try returning to the original point of entry to make any edits. See: Where do I enter a 1099-B?
Inside TurboTax, enter 1099b in the search box. This will bring you to the list of investment accounts entered so far.
Select the account and click Edit.
By completing the interview again, you should be able to edit these fields.
For other information related to investment sales, see: 5 Things You Should Know about Capital Gains Tax - TurboTax Tax Tips & Videos
