You are going to have to contact customer support. I am fairly certain there is no way to transfer character especially from an account you don't have access to.
The only way I can think of is if the character is part of a campaign. The dm might be able to unassign the character and let the new account claim it. I'd print the character sheet just in case.
Looking for help with my daughter's transferring my daughter's DnD characters to a new account because she lost access to the old account.
You are going to have to contact customer support. I am fairly certain there is no way to transfer character especially from an account you don't have access to.
The only way I can think of is if the character is part of a campaign. The dm might be able to unassign the character and let the new account claim it. I'd print the character sheet just in case.