Account Switching for Facebook Messenger Comes to iOS
If you have multiple Facebook accounts, simply go to "Me" or "Profile", scroll down and select "Switch Account", then tap on the plus sign to add the new account(s) you’d like to be able to switch between.
8 Jul 2016 ... If you have multiple Facebook accounts, simply go to “Me” or “Profile”, scroll down and select “Switch Account”, then tap on the plus sign to add ...