If you created an AWS Account via AWS Organizations, then you will need to complete the standard AWS Sign up steps since much of this information was reliant on the AWS Root Account. More details here.
You will need to add a credit card if you are on invoice billing since the account will be disconnected from the management / consolidated billing account. Otherwise you will get an error such as below:
You will have to confirm that you are human. You will have to enter your phone number and enter a verification code such as below. We recommend you hit mute on your phone, sometimes the feedback makes it fail.
You will then have to pick a support plan.
After all of the above has been completed, you should see box such as below. 🎉🎉🎉
You can now remove the account from the organization.
From the organizational root (aka management account) in your new AWS you will want to invite the other AWS Accounts into the new organization.