WARNING: This page is about a different car, the 2024 Audi S6 and 2024 Audi A6 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
-- Remove the wiper arm -2- from the rear window.
Fig 1: Pull Wiper Blade Down Out Of The Wiper Arm
Courtesy of AUDI OF AMERICA, LLC
-- Pull the wiper blade -1- downward out of the wiper arm -2- -arrow-.