Open the Messenger app
Tap your profile picture
Tap Account settings
Tap Password and security
Tap Where you’re logged in
Select the Messenger session
Tap Log out
If you use Facebook Messenger on Android
Go to Settings on your phone
Tap Apps
Tap Messenger
Tap Storage
Tap Clear data
If you use Messenger on iPhone
Delete the Messenger app
Reinstall the app
Log in again when needed
If Messenger is linked to Facebook
Open the Facebook app or website
Go to Settings and privacy
Tap Security and login
Find Messenger under logged-in devices
Tap Log out