Double your money back advice here.
I have done this with iPhones and iPads. Phones are easy. Tablets are a headache - time consuming, but not rocket science
The shield should peel off easily and it can be reinstalled. I have done so many times. But don't expect it to look as nice as first time, but with practice you can get close. Peel it off carefully. Get a flat pan and fill it with water and a mild soap - i use hand soap from a pump dispenser. Forget the container from Zagg. Not necessary. Nothing special, anyway. (The kiosks in malls that hover outside of Apple stores use a special vat full of water + probably soap. Take a clue from them.)
Soak the shield in the pan, being careful not to let the sticky side fold onto itself. But it that happens do not panic. Just peel in apart - can take some effort - do it slowly or the shield might stretch.
Rinse it off a lot, under warm water, with clean, soapy hands to remove the dust and crud that inevitably will have adhered to the stick surface. Let it drip dry a little, but make sure it is nice and wet. Put it back on the device and then use a squeegy gently and for a long time.
It takes a lot of patience with a tablet. Bubbles will be all over the place. Many more than with new shields, initial installs. After a few days, most will go away but again, not as nice as original installation. But so what? They are no really that noticeable with photos, videos, etc.
