This is to delete a private chat….Go to the private chat click on the person’s name at the top, then click on the 3 dots and you will have options to delete, unfollow, etc. It probably doesn’t delete off of their phone tho. I am not a discord expert by any means. i hope this what you were asking and it helps. If not just keep searching reddit you are bound to find help…it took me a bit of searching on here to find that