How do you check Messenger deleted chats on someone else's phone?

Secret conversations on messenger cannot be retraced as they vanish after seconds seeing it.
In a normal chat, once messages are deleted, can’t be backed up easily.

But don’t worry.

Nothing is impossible and specially in the world of internet and technology.
You just what need is a little knowledge of that.

So, without writing more here is the solution-

You can find and recover Facebook messages that have been removed from your inbox by being archived, but if you have permanently deleted a conversation, you won't be able to recover it. To find and recover messages you've removed from your Facebook inbox, log in to Facebook. Then, click the Messenger icon.

Thanks................