I need to amend my taxes due to late Schedule K. I have received my return funds from IRS, but their site shows it's not accepted or funds sent. How do I amend?

I filed my taxes with IRS on 2/13 and it was received that day.  I received my return funds on 2/23, but IRS website still shows the refund is not approved nor has it been sent.  I need to amend my 2020 return for a late schedule K, but I cannot amend until the IRS officially shows my taxes were accepted and approved.