I repaid a significant pension plan overpayment on June 2 2020. The overpayment 1099R was in my 2019 tax return. If I haven't received a tax form from the pension plan can I file an amended return before the July 15. I do have proof of payment to the pension plan. A copy of the check, tracking info, proof the check was cashed, and a copy of the overpayment letter demanding repayment.
The repayment does not change your 2019 tax return. Since you repaid it in 2020, you will report the repayment on your 2020 tax return. Depending on the amount and other factors you may be able to claim either a deduction or a credit based on the repayment.