It is not possible to switch consumers you created via the Customers API over to a different Mollie account. You would have to create them in the new account via our API. In order to avoid the consumers once again having to carry out a "first payment" to create the mandate, you can use our Mandates API to create the mandates yourself. Please take note: this is only possible for mandates via SEPA Direct Debit. After creating a mandate, direct debiting can be resumed or a subscription generated.