Change name of accounts within an organisation

Hello.

You can change the account name by signing in to the target AWS account as a root user and following the steps in the document below.
https://repost.aws/knowledge-center/change-organizations-name

To sign in to the root user of your Organizations member account, you must first reset your password.
https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_accounts_access.html#orgs_manage_accounts_access-as-root

After changing your password, you can sign in by following the steps in the document below.
https://docs.aws.amazon.com/signin/latest/userguide/introduction-to-root-user-sign-in-tutorial.html

Here is the AWS Doc which explains the steps on how to rename the account. https://docs.aws.amazon.com/organizations/latest/userguide/rename_ou.html