When prying old garage door windows off for replacement, how can I ensure they won't break?

When prying old garage door windows off for replacement, you need another person to assist you, to ensure they will not break. Your assistant should position himself in front of the garage door windows, holding the window frame as you unscrew the trim or retainers, at the back of the door. When you unfastened the first trim piece or retainer, secure the glass with masking tape, so it will not fall off as you unscrew and unfasten the rest of the trim or retainers of the window frame.