An environment at Nmbrs always has an account owner (legal owner). If it is desired that this owner needs to be changed, the current legal owner can change this via 'Contacts Information' in My Account. Note: If you as a current legal owner choose another legal owner, it is no longer possible to make changes to the contact persons. If you want to make other changes, it is advisable to make these first.
The following article shows more about 'Contacts information': Contacts Information types