If you have not already filed your return, see the steps below for entering your 1099-R.
If you have already e-filed or mailed the return, you will need to wait until the IRS has accepted it. Once they accept it and you have received your refund, then you can amend it to add that 1099-R. If it gets rejected, you can just make the needed changes and file again.
NOTE: The amend form will be ready for you in mid-February. Once amend form is ready, you can go here and get instruction https://ttlc.intuit.com/questions/1894381 for amending that return
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