The owner is not shown the item: a farm cannot be left without a keeper. To leave, the owner first transfers ownership to another member or deletes the whole farm.
A farm administrator can leave: leaving is a person's right, not a power over others.
The operation is IRREVERSIBLE and happens at once. There is no cooling-off period.
Your username, password, email address and every way of signing in disappear - password, Google, LINE. Signing in to the farm after that is impossible.
The username and the address are freed: you will be able to sign up again, and your former username may be taken by someone else.
THE FARM HISTORY STAYS, and this is not an oversight but how the product is built: everything you did - plantings, moves, harvests - stays in the farm log signed with your name. Those records belong to the farm, not to your account, and leaving does not delete them.
Your contacts are kept nowhere: the address and the phone go away with the account. Only the name stays in the history.
The farm's plants, boxes and catalogues are not touched: one member leaving does not change the holding.