If a person with approved documents is already registered to an account, you can easily transfer them to another.
Head over to "My Models" and click on the account where you want to add the person, then “Add Person” > “Select Existing Person”.
Now you will see a list of all the persons with approved documents in your studio, and their current model accounts. Select the one(s) you want to transfer and hit “Copy Persons”. The selected person(s) will be copied to the new account and will also stay in their current one.
Let’s say that you want to add a person to account B and remove them from account A. In this case, you have to copy them to account B first, and only after remove them from account A.
Remember that you can’t have more than 6 people per model account. Moreover, models can only have one single model account, and multiple couple/group accounts as long as the combination of people is different.