You can move an already existing Leadfeeder account under another Leadfeeder company. That Leadfeeder company will end up having two accounts. You will need to be an admin in both, the added Leadfeeder account as well as the receiving Leadfeeder company (and its current account(s)) to perform this action.
This is useful if you need to merge two different Leadfeeder accounts that are not connected yet.
Log in to the account you want to add and click Personal settings/Account/Details.
Click on "Change" button and choose which company you wish to move this account under from the drop-down list.
Click the "Save" button and you are done. Also please remember that you have to change the tracker script on the website of the Leadfeeder account you just moved. You need to add the script hashed ID of the Leadfeeder company you moved it under to keep the website tracking.