I have a 3D Cartesian FLASH dataset that I would like to mirror about the z=0 plane for volume rendering. Is there a straightforward way to do this in yt?

I was unable to find any option in the volume rendering itself. My guess is that I'd have to perhaps make a new array representing the data and do the mirroring by appropriately copying the elements. However, I'm unsure how to go about this--especially for AMR data. Does anyone know of any built-in functionality that might be useful for this?