You can delete the 1099 information from the tools menu ( delete a form). You will want to delete all related forms then go back and import again. However, below is more on deleting forms in TurboTax:
https://ttlc.intuit.com/replies/3434007
To Delete a form (TurboTax Online):
- Open your return
- Go to Tools on the left hand side of your screen
- Then select Delete a form
- Then choose the 1099-B and any related worksheets.
- Follow the prompts
