How to add a host or transfer account profile over to another participant

There are a few ways you can handle this: 

• If its a generic account, they can just change the sign-in email for the account to something you would prefer to use. That would allow you to have access and control over that account and all meetings associated with it. 
• If its a paid account with at least 2 licenses, you can be added to the account as a separate user, assigned a license, then set up scheduling privilege to transfer the meetings between 2 licensed users.