Here on the new page you numerous options are visible but you need to hit on “Settings” tab, available on the top right as visible in the picture given below:-
Now you will be directed to the next window, having various settings links but you need to follow the “ACCOUNT ACTION” tab and from the drop-down list of it you should select “Clear Conversation” tab.
The names of chatters will be seen on your digital display as:
Step 6. You need to hit on “Cross” sign in front of that person identify, whose chat you want to delete.
Step 7. Massages or conversation of that chat would be removed in few seconds
Step 8. Now you should go back to the massage section to check if the messages have been deleted.