If you have already e-filed or mailed the return and they accept it, then you will need to wait until you have received your refund. Then, you will need to amend that return to make changes (add your 1099-R). You will need to send in any forms that caused the need for an amendment (Original 1040 Form, new 1040X Form and 1099-R. Print, sign and mail your forms to the IRS.
