You would have to do that in the model. You can change the size of the whole model but not just part of it.
Thanks for your question
You would have to import the model into an external 3D software (3Ds Max, Maya, Blender as example) and scale up the specific parts of the model there. Within Studio the scale tool applies to all of the model and not selected parts. Even so, the format of the dog model is a POD file, meaning that it unfortunately cannot be imported into 3D software.
Hope this helps,