Go to the bottom of the trousers and open the Velcro tab
Once opened you should have access to the ankle zip
Once open this is what you should see
Open the hidden Velcro strip - this is sewn under the zip on the same side as the velcro tab
Once opened you can access inside the trousers, and feel for the armor pocket. Pull the pocket down and out of the opening
Open the Velcro tab on the pocket and remove the knee armour!