If you missed the deadline due to a reasonable cause, you may ask the IRS to waive the 50% excise tax.
You will need to Form 5329 to calculate the excise tax on
your missed Required Minimum Distribution. You will not receive a
1099-R to report the 2017 done in January of 2018 until next year.
You can access Form 5329 by going into your Forms at the top of the screen. On
the left side, click on Open Form and type in 5329 in the Search box. Double-click on the form and it brings it into
your right-side so you can fill it out. The Waiver Request can be typed
or printed to include with the forms separately.
The request for waiver may
be included in a letter of explanation,
which you attach to your tax return (Form 1040)
along with your Form 5329. When requesting a waiver, do not pay the excess accumulation penalty up front.
Instead, follow the instructions for requesting a waiver in the Instructions for Form 5329. If the IRS does
not honor your waiver request, you will be notified and send a bill.
The 1040, Form 5329 and the waiver request must be
filed by mail.
Instructions for
Form 5329: https://www.irs.gov/pub/irs-pdf/i5329.pdf