How To Sign Out Facebook Messenger
Well, it's not possible to sign out from within the Messenger but there is an easy workaround to do so if you're utilizing an Android device. iPhone, iPad and WP users can also logout without uninstalling the app however that needs utilizing Facebook's web interface, either from your mobile internet browser or desktop. Though, this isn't a user friendly way however will do the needed task.
Logout from Messenger on Android
Go to phone Settings > Applications and open the Messenger app. Click the 'Clear data' option and now open Messenger. You'll now able to log into Messenger utilizing a various Facebook account. Note: If you've Facebook app installed and you're singed into it then Messenger will still reveal your previously linked account that can be configured right now.
To check in utilizing a different ID, just click the 'Change Account' alternative. In case you wish to unlink your earlier account from Messenger, just logout from Facebook app.
Note: Cleaning data will eliminate the app settings and all your messenger information (stored in your area) such as photos. However, the messages and photos will be synced once again with your account. Follow the below alternate treatment instead, if you don't desire the information to be rubbed out.
Logout from Facebook App/ Messenger App on iOS, Android, Windows Phone and Desktop (Recommended Approach).
This is a really helpful method to from another location logout from Facebook from any or all of the gadgets to which your Facebook account is related to. It comes real helpful in case you loose access to a specific device and want to prevent unauthorised access to your account. The advantage of this workaround is that it does not wipes your local Messenger data and deals with all major mobile OS like iOS (iPhone, iPad, iPod touch), Android and Windows Phone.
To do so, log into your Facebook account from your desktop browser or usage Chrome internet browser to log into facebook.com on your smartphone and go with desktop variation of the website. In Facebook, browse to Settings > Security and click on "Where You're Logged In" alternative.
Here you can see all your Facebook active sessions in addition to information like Device type. Select the Messenger one and click on "End activity". Now open Messenger on your phone and it'll automatically log off (wait for an instant and ensure you're connected to Internet.).
Dear Facebook, please do not frustrate users by pulling off standard functionality. Take that! And one more thing please don’t forget to share this awesome trick to use the How To Sign Out Facebook Messenger with your friends.