Can I scale down a terrain I have made with the resolution of 500x500?

Hi. I am working with AR using vuforia, and I have created a scene with a customized terrain and some 3d objects. When I open a sample scene from vuforia and replace the existing 3d objects with my scene I can scale them to fit the ImageTarget. But my terrain will not scale. Does anyone know a way to take my alreade created terrain and make it smaller, or some other way to work around this? I am not talking about the width/height in terrain tools menu.

Help to solve this will be much appreciated. Thanks!