Ash here from the Shopify team. I'm happy to help out!
I understand you're trying to update the EIN associated with your Shopify Payments account. In order to assist, I'll need to authenticate you on the account in question and loop in our payments team. I've sent you an email to the email address associated with your Shopify Community account. Please reply back to that email, and once I hear from you we can proceed with your request!