Error changing billing details: unknown field vatRate

This sounds like a bug in the Sanity billing interface. The vatRate field error you're encountering when trying to update the invoice recipient email address is not a documented issue, and it shouldn't be blocking you from making this change.

Here's what I'd recommend:

Immediate solution: Contact Sanity support directly at support@sanity.io with the following details:

• The specific error message you're seeing (including the full "unknown field vatRate" error)
• The organization name or project ID where you're experiencing this
• Screenshots of the error if possible
• What browser you're using

Since this appears to be a platform bug rather than a configuration issue, the support team will be able to either fix it on their end or provide you with a workaround.

Where billing details are managed: You should be able to change invoice recipient email addresses through manage.sanity.io in your organization settings. Organizations are the top-level billing entities in Sanity where payment details, contact information, and invoice settings are managed.

Why this is likely a bug: The vatRate field isn't something you should be interacting with directly when updating email addresses - it's an internal billing calculation field. The fact that it's throwing an "unknown field" error suggests there's a validation issue in the billing form that the support team needs to address.

The support team is generally quite responsive to billing-related issues since they understand these are blocking business operations. Don't hesitate to reach out to them directly at support@sanity.io.