Normally even when I don't sync my phone with my computer, when I turn on the Messages app on my Mac, I will see the latest messages even if they already have been deleted on my iPhone. I noticed today that the last messages that synced to my Mac was from 7/30. Is there a way to update the messages on my Mac?? I just happen to notice it now because I needed to retrieve an iMessage conversation that is no longer on my phone.