Hey there! If you've got the most updated version of Message+ which it sounds like you do, they added a quick delete to conversations. Just swipe the conversation itself to the left and the delete option should come up. Then just confirm it wasn't an accidental swipe and bam, done! You still have the confirm but it's a very quick swipe and tap process as opposed to the tap and hold etc. That's actually designed for deleting multiple conversations at once. I've got it on my Galaxy S5 so it should be the same process on the note 4 but if it doesn't work let me know and I'll mess with my wife's note 4 to figure it out later tonight.