When you missed your required minimum distribution (RMD), you should have sent in a letter of explanation and filed IRS Form 5329 with your tax return. If you did not do so, you will still need to file your Form 5329 and attach the letter of explanation.
The letter should include an explanation of why you missed your RMD deadline, and explain when you distributed the amount from your retirement account. It should also include a request to the IRS to waive the 50% excess accumulation penalty. Once that is sent in, you can do nothing other than wait to see if the IRS denies your request. If you do not receive a response, it is usually an indication that your request has been approved.
For more insight, see Missed Your RMD Deadline? What To Do and Retirement Plan Tax Forms You May Need To File - Part 1.
This question was answered by Denise Appleby