I already file my tax return for 2020 and it was accepted and I got refund check. Today I got a mail that has K-1 form from a partnership related to an ETF I bought in 2020. I checked the K-1 form that has blank in most fields and 0 amount in interest in come, net short-term capital gain (loss), other deductions,... Obviously this will not change my tax return at all. What should I do?