iFixit

Maintaining your hold on the keyboard, lay the casing flat and gently bow the keyboard until the two tabs on either side of the keyboard come free.

Slide the keyboard away from the trackpad and out of the upper case.

When reversing the steps and installing the new keyboard, be sure to carefully insert the keyboard ribbon and the keyboard backlight ribbon into their respective slots in the upper case before reinserting the tabs on either side of the keyboard.