You can remove your Form 1099-B imported stock transaction information by deleting Form 1099-B, Schedule D and associated Capital Gains Worksheets from TurboTax.
You can remove unwanted forms, schedules and worksheets in TurboTax Online - please see the following TurboTax FAQ, "How do I delete
forms in TurboTax Online?":
https://ttlc.intuit.com/replies/3288508