I try to change brand on edit page but failure. So I open a case just received such reply:
Before we can process your request, we need you to provide one of these valid forms of documentation:
What proof I must provided to change brand, I try it several times but failure.
The brand is my brand, the listing was also created by myself, why cannot I change its brand?
Once a brand is on an Amazon page, it is there to stay. Businesses don’t like to change brand names, it is expensive and a lengthy procedure. You will need to create a new page for the brand, it will be much easier.