https://techcrunch.com/2019/02/05/facebook-messenger-remove/

Facebook has finally made good on its promise to let users unsend chats after TechCrunch discovered Mark Zuckerberg had secretly retracted some of his Facebook Messages from recipients. Today Facebook Messenger globally rolls out “Remove for everyone” to help you pull back typos, poor choices, embarrassing thoughts, or any other message.

For up to 10 minutes after sending a Facebook Message, the sender can tap on it and they’ll find the delete button has been replaced by “Remove for you”, but there’s now also a “Remove for everyone” option that pulls the message from recipients’ inboxes. They’ll see an alert that you removed a message in its place, and can still flag the message to Facebook who’ll retain the content briefly to see if its reported. The feature could make people more comfortable having honest conversations or using Messenger for flirting since they can second guess what they send, but it won’t let people change ancient history.