If you have messages in Facebook messenger and you want to delete it then, click on the top-right of the Facebook, after that click on See All in Messenger appears at the bottom. Open the conversation which you want to delete and below chats, navigate your mouse over the conversation which you want to delete, and choose Delete. Call on +44-800-368-9064 if you are facing any issue while doing this. For more information to visit this website: http://www.customecaresupportnumber.co.uk/facebook-help.php