Palm Pre Plus - Manual (Page 165)

Chapter 11 : Troubleshooting 165
3 Turn the phone completely off (see Turn everything (the screen and
wireless services) on/off ).
4 Press and release the back cover release .
5 Slide your thumbnail or a credit card into the hairline opening between
the back cover and the phone, starting at the bottom and moving
halfway up one side until you hear the clasp (x) release.
6 Repeat step 5 to release the clasp (y) on the other side of the phone.
7 Lift off the back cover.
8 Remove the battery by pulling the tab that appears at the top of the
battery.
9 Insert the new battery .