Package identity prefix still shows the former company name after a publisher rename -- can it be corrected?

We renamed our company and updated the Partner Center account. The publisher display name and the Windows Publisher ID both show the new name, and the account re-verified successfully.

The package identity did not follow. Reserving our first product name produced:

• Package/Identity/Name --> OldCompanyName.ProductName
• Package Family Name (PFN) --> OldCompanyName.ProductName_<publisher-id>
• Package/Properties/PublisherDisplayName --> NewCompanyName

Deleting the reservation and reserving again produced the same prefix, so it appears to be held at the account level rather than per product.

We have published nothing -- no submitted products, no certified packages, no installations anywhere.

Searching here gives conflicting answers. Several older threads say the package identity name can never be changed. Another suggests the Package Family Name does change when the publisher name changes, which would imply the opposite. Which is correct, and is there any route to correcting the prefix on an account with nothing published?

(We also have an unanswered support request about this; asked separately.)