The Marketplace team does not have the ability to transfer, merge, or swap purchases between different accounts. The available option is to provide shared access between accounts:
https://partnersupport.magento.com/hc/en-us/articles/360035164572-Shared-Access
To avoid a refund/repurchase situation if allowed by policy (25 days after purchase), please assure that the account being used for purchasing is the owner of the Magento instance.