Can an amended return be filed for a (2016) tax return that was filed late, after the due date, when the due date of the original return was over 3 years ago?

[Quartzite]

I have a client who filed her 2016 tax return last year, 2019, and would like to file an amended return for it. It is still within 3 years of filing her return, although it is more than 3 years since the original due date April 15, 2017. I'm having trouble finding out whether we can amend her return. Thanks!

[IRonMaN]

It took them three years to file and they still couldn't get it right?  Directly from the horse's mouth:

When to File

Generally, to claim a refund, you must file Form 1040-X within 3 years after the date you filed your original return or within 2 years after the date you paid the tax, whichever is later. Returns filed before the due date (without regard to extensions) are considered filed on the due date, and withholding is deemed to be tax paid on the due date. Special rules apply for refund claims relating to net operating losses, foreign tax credits, bad debts, and other issues. For more information, refer to the Instructions for Form 1040-X.

[BobKamman]

Of course she can file an amended return.  Can she get a refund?  Only of what she paid with the original return last year.