You'll be able to unsend Facebook messages, eventually
https://www.techradar.com/news/youll-be-able-to-unsend-facebook-messages-eventually
News broke last night that Facebook CEO Mark Zuckerberg and other executives at the social network unsent their messages retracting them from recipients' inboxes.
Facebook told TechCrunch, which has email evidence showing messages that were deleted, that it retracted the messages "to protect our executives' communications" following the Sony Pictures email hack of 2014.