You can reassign a Farm using either the mobile app or the web app.
Important: Fields themselves cannot be reassigned directly—only Farms can. If you need to move a field to another user, first place that field under an existing or new Farm, then reassign the Farm to the new user. Once the Farm is associated with the new user, you can move the field to a different Farm if needed.
Watch below how to reassign a Farm on the web:
Watch below how to reassign a Farm on the mobile app: