Dropbox is a cloud storage service which allows you to backup photos, videos and files to access them from any mobile device, computer or tablet. You can share your photos, videos and files with other people in the world. You can link your account by downloading and installing 'Dropbox' app on your Android phone. Whenever you want to unlink your Android phone from Dropbox app, tap 'Menu' button from the Dropbox app and tap 'Settings'. You will see the 'Unlink Device from Dropbox' button. Tap it and then tap 'Unlink Device' button to confirm it.