2. When prompted, use the QR scanner within WhatsApp to scan it. To do so, open WhatsApp on your phone.
On Android: in the Chats screen > More Options > WhatsApp Web.
On iPhone: go to Settings > WhatsApp Web
Log out of Desktop from WhatsApp
Go to WhatsApp on your phone > Settings or Menu.
Tap WhatsApp Web > Log out from all devices > Log out.