In Blender 3.0, I have linked a character (created in another file) into the current scene. I enabled Library Overrides and I can change the pose of the character... but unfortunately I can't change its material (I'm mostly interested to change the base color). Is it possible? I need it to quickly see which color best matches the scene colors.
EDIT
I tried the proposed answer, but I get an error "Indirect Library data-block, cannot change".