Schedule K-1 and Box 16 and filing by April 15th if filing by mail

[Ciao4]

I file my returns by mail.

My Schedule K-1 has Box 16 checked but Schedule K-3 won't be ready until June.

Do I need to uncheck Box 16 if I mail return?

Could I send if my return and then amend the return when the K-3 is released in June?

I will have a large refund.

With the info below I doubt I will owe much.

Since I expect a large refund, would I be subject to a penalty if I don't file an extension?

Box 21 , Foreign Taxes Paid is blank.

I have $18 in distributions,

$5 loss in Box 1.

Ordinary dividends of $2

[robtm]

Why wouldn't you want to file an extension? That would be the easiest way to handle it rather than mess with an amended return. Just be sure you will get a refund and not owe any taxes.