If you have already e-filed your returns and they have been accepted, you will need to amend them with a Form 1040-X. If your returns are rejected, you will be able to add the 1099-B, and delete the extra form.
Form 1040-X has just been made available. You will be able to electronically file your amended return. Search for 1040-X and click on the Jump to link.
Here is a TurboTax help article with more information about amending a return.
[Edited 02/25/22 |4:47 PM PST]
@mccakev
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