Apply a suction cup to the back of the phone, as close to the center of the right edge as possible (where the adhesive is narrowest).

Pull on the suction cup with strong, steady force to create a gap between the back cover and the frame.

Insert the point of an opening pick into the gap.

If you are having trouble creating a gap, your best bet is to apply more heat to the edge and try the previous step again.

You can try applying a few drops of high concentration (over 90%) isopropyl alcohol into the seam to help loosen the adhesive.