Gather all the information regarding the license (Original entitlement ID, serial number or mac address associated, account under which it was redeemed), and :
Make sure the new account is properly created;
If the new account is under the same domain, you do not need any additional permissions; but if it is under a partner or a different domain name (company) you will need permission from the owner of that account to transfer the license to the new account;
Open a GTAC Support case to log all the information;
The GTAC together with Licensing will proceed with the steps to transfer the license. Once it is completed, the new account manager can see and rehost the licenses as needed, under "my licenses" in their extranet page.