I generally concur with @Critter's replies.
However, pursuant to Rev. Proc. 2015-13 and Treas. Reg. §301.9100-2, and in compliance with the relevant section of Rev. Proc. 2015-13, an amended return for the 2018 tax year could be filed along with Form 3115. There is an automatic 6-month extension provided the original return was timely filed.
Regardless, this procedure is extremely complex and should not be attempted as a DIY project. Professional tax preparation and/or guidance is highly recommended.
