i received replacement protective glass undercwatranty that needs to be replaced by apple

Hello~ Are you referring to a screen protector or is the screen protector itself broken? Perhaps the back glass? *Lotus Pilot* has given excellent great information how to replace your screen protector but Apple can also can also do that for you usually without an appointment. If it is a broken screen or back glass then you will definitely need an appointment…either way here’s how to make an appointment if needed…

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~Katana-San~

Perhaps you refer to a screen protector?

If so, this can be simply replaced yourself. Gently lift the damaged screen protector at its corner - and very slowly lift the screen protector, allowing the adhesive to "relax" as you peel the screen protector from the underlying screen.

The replacement screen protector should have application instructions.