A changeling's Change Appearance states:

You also can't appear as a creature of a different size than you, and your basic shape stays the same; if you’re bipedal, you can’t use this trait to become quadrupedal, for instance.

But seeing that with a druid's Wild Shape can change you into a creature that is quadrupedal and a differerent size than yourself, does this mean that after that you can change into another quadrupedal creature of that same size?

Let's say you are a normal 2 legged medium changeling and you Wild Shape into a 4 legged large saber-toothed tiger. Does that mean that you could use the Change Appearance feature of the changeling to change into another 4 legged walking large creature like a dire wolf? Could you also Change Appearance into a creature outside of the possible druid Wild Shapes? For example a creature with a higher CR?