Simple! You go settings > storage > tap on SD card bar > scroll to bottom > tap on safely remove SD card. I just did it yesterday when I got my new 830. It didn't duplicate anything. Once you have the new phone up and running just pop it in.I'm getting a replacement 1520 in a few days and I was wondering what the procedure is for restoring backups and also moving the SD card.
I'm worried if I move the SD card and do a restore that it will duplicate the contents on the card.