To transfer a POEditor organization to another user (thus making them the new organization owner), you need to go to your personal account, access Account Settings > Organizations and click Leave.
If there are other POEditor users who have access to the organization, you'll be able to leave the organization to one of them (provided that their account is activated).
If you're not the owner of the organization and just want to quit being a manager, you can leave the organization by logging on to your user, going to Account Settings > Organizations and clicking Leave.