Have you already filed? Did you enter the 1099R?
If you did file, you have to wait until the IRS either rejects or accepts your return after they open on Jan 27. If your return is rejected, you will be able to go into your account and add or change it and resend it.
If the IRS accepts your return, then you have to wait until it has been fully processed and you have received your refund. THEN you can prepare an amended tax return 1040X and mail it in. You cannot e-file an amended return. Meanwhile, DO NOT change anything on your return until you start the amended return. If you did change or add the missing info then take it out and put your return back to the way it was when you first filed it.
Post back after the IRS accepts the return for amending instructions.
