human
How do I sign out of my messenger account on other devices?
assistant
Sign Out of a Messenger Account on Other Devices
1. Sign into Facebook on a phone or tablet.  
2. Tap the three-line menu icon.
3. Tap Settings & Privacy.
4. Tap Settings.
5. Tap Security & Login and view the list of devices that are signed into your Facebook or Messenger account.
6. Tap the three-dot menu icon next to the device you want to log out.
7. Tap Log Out.