They are created by the account Admin to manage their events which will be also assigned to them by the account manager.
Teammates can only control the events they are assigned to control. For example, if the account admin assigned project A to teammate A, he will be able only to see and control project A and he will not be able to see or control other projects.
Teammates can not add any person from outside the organization to check or assist them within the event. They can only invite members approved by the account admin from the beginning.
In case the teammates found that they need to increase or decrease the seats for their event, they need to inform the account admin to manage it from his end.
To go back to billing and accounts article, visit https://app.intercom.io/a/apps/n8lkar39/articles/articles/1985140/show