Can I remove a duplicate dividend entry on Schedule B on E-filed return?

If you already filed your return, you can't make any changes, you may need to amend your return.

Wait until the IRS either accepts or rejects your return. If they reject your return, you can make the correction and resubmit. 

If they accept your return, wait until you receive your refund then amend the return. 

How do I amend my federal tax return for this year?

To revisit the dividend section:

1. Sign in to your TurboTax account and open or continue your return
2. Select Federal from the menu, then Wages & Income
3. Locate the section titled Investments & Savings and select Show More, then select Start or Revisit next to Dividend on 1099-DIV