You will need to add the 1099-B to your return. Since you have already filed you will need to wait until
the IRS either rejects or accepts your return. In the meanwhile, do not go in and make any changes to your return.
- If
your return is rejected, you will be able to
go into your account and make the necessary changes and re-submit your
return.
- If the IRS accepts your return, you must wait
until it has been fully processed and you receive your refund or have paid
your balance due to amend. You will need to prepare an amended tax return
on a 1040X and mail it in if the new info changes your refund or tax
due amount. You cannot e-file
an amended return. They have to be mailed, and it takes up to 16 weeks for the IRS to process an
amended return. 3 weeks after you mailed your amendment, you can start
tracking its progress at the IRS Where's
My Amended Return? site.
Amendment instructions can be found
here: https://ttlc.intuit.com/replies/6602208
