Web app: click the switch icon on the top left corner next to your organization's name. Click to switch organizations.
The My Organizations section displays organizations where you are either the owner, admin, or co-worker. You can also switch to your Personal Space from this dropdown.
The My External Contacts section displays organizations where you are an external contact.
The My Service Providers section displays organizations where you are a client.
Mobile app: tap either the button on the top left corner or your organization's icon or name to switch organizations.
