Caution: the back pad is secured with glue so remove it gently to avoid ripping the pad. You may have to repeatedly pull and release to loosen up the glue.
First start by peeling off the outer rubbery covering on the bottom of the device. This part is very fragile, so it is recommended that a blow dryer is used on the covering to heat it up. Simply blow dry the covering while slowly peeling it away, and the covering will not tear.
Continue peeling back on the pad until it is removed.