Removing from the inside
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2015 BMW Alpina B7L, 2015 BMW Alpina B7, 2015 BMW 750i, 2015 BMW 750Li, and 2015 BMW 740i. However, it is still accessible from the selected car via links, so may be relevant.
Guide knife carefully between body and window glass.
Run blade of knife parallel to glass.
Take care not to damage paintwork.
Cut through adhesive bead all the way around.
Pull window glass outwards to remove.