schedule k-1, 1041 form after taxes filed

The IRS has a FAQ: [Amended Returns & Form 1040X][irs1

What should I do if I made a mistake on my federal return that I've already filed?

Answer:

It depends on the type of mistake you made:

• Many mathematical errors are caught during the processing of the tax return and corrected by the IRS, so you may not need to correct these mistakes.
• If you didn't claim the correct filing status or you need to change your income, deductions, or credits, you should file an amended or corrected return using Form 1040-X, Amended U.S. Individual Income Tax Return.

They even have a tool: Should I File an Amended Return?

So if the K-1 changes your income, then you will have to file an amended return.